Prelims Solution

The increase in the price of a certain item was 25%. Then the price was decreased by 20% and then again increased by 10%. What is the resultant increase in the price?

CSAT 2022 /

Q. The increase in the price of a certain item was 25%. Then the price was decreased by 20% and then again increased by 10%. What is the resultant increase in the price?

a. 5%
b. 10%
c. 12.5%
d. 15%
Correct Answer: b. 10%

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 
Let’s assume the initial price of the item to be x.

After a 25% increase in price, the new price will be:
x + 0.25x = 1.25x

Next, the price is decreased by 20%. The new price will be:
0.8(1.25x) = 1x

Finally, the price is increased by 10%. The new price will be:
1.1(1x) = 1.1x

To find the resultant increase in price

we need to find the percentage increase from the initial price x to the final price 1.1x:
Resultant increase = [(1.1x – x) / x] x 100%
= (0.1x / x) x 100%
= 10%

Therefore, the resultant increase in the price is 10%. The correct answer is (b).

The increase in the price of a certain item was 25%. Then the price was decreased by 20% and then again increased by 10%. What is the resultant increase in the price? Read More »

Q. In a tournament of Chess having 150 entrants, a player is eliminated whenever he loses a match. It is given that no match results in a tie/draw. How many matches are played in the entire tournament?

CSAT 2022 /

Q. In a tournament of Chess having 150 entrants, a player is eliminated whenever he loses a match. It is given that no match results in a tie/draw. How many matches are played in the entire tournament?

a. 151
b. 150
c. 149
d. 148
Correct Answer: c. 149

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 

In a tournament of Chess

In a knockout chess tournament like this, each player is eliminated after losing a match. Since there are 150 entrants, only one player remains undefeated at the end of the tournament, and this player is the winner.

To find out how many matches are played, we can think about it in terms of elimination: for every player except the winner, they have to lose exactly one match to be eliminated. Since there are 150 entrants and only one winner, 150 – 1 = 149 players need to be eliminated.

Each elimination comes from one match, so there are 149 matches played in the entire tournament.

Q. In a tournament of Chess having 150 entrants, a player is eliminated whenever he loses a match. It is given that no match results in a tie/draw. How many matches are played in the entire tournament? Read More »

Which number amongst 2^40, 3^21, 4^18 and 8^12 is the smallest?

CSAT 2022 /

Q. Which number amongst 2^40, 3^21, 4^18 and 8^12 is the smallest?

a. 2^40
b. 3^21
c. 4^18
d. 8^12
Correct Answer: b. 3^21

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 

Which number among is smallest:

2^40, 3^21, 4^18, and 8^12

We can also write them as: 2^40, 3^21, 2^36, and 2^36.

We can rewrite 2^36 and 3^21 as:
2^12 and 3^7
4096 > 2187
Hence, 3^21 is the smallest number.

Which number amongst 2^40, 3^21, 4^18 and 8^12 is the smallest? Read More »

Q. A bill for Rs. 1,840 is paid in the denominations of Rs. 50, Rs. 20 and Rs.10 notes. 50 notes in all are used. Consider the following statements:

CSAT 2022 /

Q. A bill for Rs. 1,840 is paid in the denominations of Rs. 50, Rs. 20 and Rs.10 notes. 50 notes in all are used. Consider the following statements:

1.  25 notes of Rs. 50 are used and the remaining arc in the denominations of Rs.20 and Rs. 10.
2. 35 notes of Rs.20 are used and the remaining are in the denominations of Rs. 50 and Rs. 10.
3. 20 notes of Rs.10 are used and the remaining are in the denominations of Rs. 50 and Rs. 20.
Which of the above statements are not correct?
a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2 and 3
Correct Answer: d. 1, 2 and 3

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 

A bill for 1840

Statement 1: 25 notes of Rs. 50 were used. So, remaining amount = 1840 – (25 × 50) = 1840 – 1250 = Rs. 590.
Even if all the remaining 25 notes are of Rs. 20 denomination, we will only get Rs. 500. So, Statement 1 is definitely incorrect.

Statement 2: 35 notes of Rs. 20 were used. So, remaining amount = 1840 – (35 × 20) = 1840 – 700 = Rs. 1140.
Even if all the remaining 15 notes are of Rs. 50 denomination, we will only get Rs. 750. So, Statement 2 is definitely incorrect.

Statement 3: 20 notes of Rs. 10 were used. So, remaining amount = 1840 – (20 × 10) = 1840 – 200 = Rs. 1640.Even if all the remaining 30 notes are of Rs. 50 denomination, we will only get Rs. 1500. So, Statement 3 is definitely incorrect.

A bill for 1840

Q. A bill for Rs. 1,840 is paid in the denominations of Rs. 50, Rs. 20 and Rs.10 notes. 50 notes in all are used. Consider the following statements: Read More »

An Identity Card has the number ABCDEFG, not necessarily in that order, where each letter represents a distinct digit (1, 2, 4, 5, 7, 8. 9 only). The number is divisible by 9. After deleting the first digit from the right, the resulting number is divisible by 6. After deleting two digits from the right of original number, the resulting number is divisible by 5.

CSAT 2022 /

Q. An Identity Card has the number ABCDEFG, not necessarily in that order, where each letter represents a distinct digit (1, 2, 4, 5, 7, 8. 9 only). The number is divisible by 9. After deleting the first digit from the right, the resulting number is divisible by 6. After deleting two digits from the right of original number, the resulting number is divisible by 5. After deleting three digits from the right of original number, the resulting number is divisible by 4. After deleting four digits from the right of original number, the resulting number is divisible by 3. After deleting five digits from the right of original number, the resulting number is divisible by 2.

Which of the following is a possible value for the sum of the middle three digits of the number?
a.  8
b.  9
c. 11
d. 12
Correct Answer: a. 8

Question from UPSC Prelims 2022 CSAT Paper

Explanation : 

An Identity Card has the number ABCDEFG

The number ABCDEFG is divisible by 9. Since the sum of the digits of a number divisible by 9 is also divisible by 9, we know that A+B+C+D+E+F+G = 1+2+4+5+7+8+9 = 36.

After deleting the first digit from the right (G), the resulting number ABCDEF is divisible by 6. This means that F must be even (2 or 8) and the sum of the digits (A+B+C+D+E+F) must be divisible by 3.

After deleting two digits from the right (FG), the resulting number ABCDE is divisible by 5. This means that E must be 5.

After deleting three digits from the right (EFG), the resulting number ABCD is divisible by 4. For a number to be divisible by 4, the last two digits must form a number divisible by 4. So, CD must be one of the following pairs: 12, 24, 28, 52, 72, 92.

After deleting four digits from the right (EFGD), the resulting number ABC is divisible by 3. This means that the sum of A, B, and C must be divisible by 3.

After deleting five digits from the right (EFGDC), the resulting number AB is divisible by 2. This means that B must be even (2 or 8).

Now let’s use this information to find the possible value for the sum of the middle three digits (C, D, and E).

Since E is 5, and B is even (2 or 8), we can eliminate the pairs 52 and 92 for CD, as they would require B to be odd. We are left with these possibilities for CD: 12, 24, 28, 72.

Consider CD = 12. Then, A = 7, B = 8, C = 1, D = 2, E = 5, F = 4, and G = 9. The conditions for divisibility by 9, 6, 5, 4, 3, and 2 are satisfied with 7815249. The sum of the middle three digits (C, D, and E) is 1+2+5 = 8.

In this case, the correct answer is (a) 8.

An Identity Card has the number ABCDEFG, not necessarily in that order, where each letter represents a distinct digit (1, 2, 4, 5, 7, 8. 9 only). The number is divisible by 9. After deleting the first digit from the right, the resulting number is divisible by 6. After deleting two digits from the right of original number, the resulting number is divisible by 5. Read More »

Q. Among the following Tiger Reserves, which one has the largest area under “Critical Tiger Habitat”?

Prelims 2020 GS Solution /

Q. Among the following Tiger Reserves, which one has the largest area under “Critical Tiger Habitat”?

a) Corbett
b) Ranthambore
c) Nagarjunasagar-Srisailam
d) Sundarbans
Correct Answer : c) Nagarjunasagar-Srisailam

Question from UPSC Prelims 2020 GS Paper

Explanation:

Tiger Reserves (wiienvis.nic.in)

 

Nagarjunsagar Srisailam Tiger ReserveAndhra Pradesh3,296.31 Sq.Km.

Q. Among the following Tiger Reserves, which one has the largest area under “Critical Tiger Habitat”? Read More »

Q. Consider the following statements: 1. Jet streams occur in the Northern Hemisphere only.

Prelims 2020 GS Solution /

Q. Consider the following statements:

1. Jet streams occur in the Northern Hemisphere only.
2. Only some cyclones develop an eye.
3. The temperature inside the eye of a cyclone is nearly 10ºC lesser than that of the surroundings.
Which of the statements given above is/are correct?
a) 1 only
b) 2 and 3 only
c) 2 only
d) 1 and 3 only
Correct Answer : b) 2 only

Question from UPSC Prelims 2020 GS Paper

Explanation:

1. Jet streams occur in both the Northern Hemisphere and the Southern Hemisphere.

Jet streams are fast flowing, narrow air currents found in the atmospheres of some planets, including Earth. On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds (flowing west to east). They occur in both the Northern Hemisphere and the Southern Hemisphere. Therefore, the assertion that jet streams occur only in the Northern Hemisphere is false.

2. Only some cyclones develop an eye.

The eye of a cyclone is a region at the center of a cyclone in which the weather is calm and the sky is clear or only partially covered by clouds. Not all cyclones develop a well-defined eye; it is characteristic of strong tropical cyclones (notably, hurricanes and typhoons). The formation of an eye is associated with the maturity of the cyclone, and weaker cyclones may not develop an eye at all.

3. The temperature inside the eye of a cyclone is nearly 10ºC lesser than that of the surroundings.

This statement is incorrect. In fact, the temperature inside the eye of a cyclone is warmer than its surroundings. The eye is warmer partly because of the sinking air within it, which compresses and warms up. The temperature difference can contribute to the cyclone’s intensity. The exact temperature difference can vary, but the key point is that the eye is warmer, not cooler, than its surroundings.

Q. Consider the following statements: 1. Jet streams occur in the Northern Hemisphere only. Read More »

Q. Consider the following statements: 1. 36% of India’s districts are classified as ‘overexploited’ or ‘critical’ by the Central Ground Water Authority (CGWA).

Prelims 2020 GS Solution /

Q. Consider the following statements:

1. 36% of India’s districts are classified as ‘overexploited’ or ‘critical’ by the Central Ground Water Authority (CGWA).
2. CGWA was formed under the Environment (Protection) Act.
3. India has the largest area under groundwater irrigation in the world.
Which of the statements given above is/are correct.
a) 1 only
b) 2 and 3 only
c) 2 only
d) 1 and 3 only
Correct Answer : b) 2 and 3 only

Question from UPSC Prelims 2020 GS Paper

Explanation:

India’s Groundwater Situation

According to the CGWA, approximately 12-14% of India’s districts fall under the ‘overexploited’ or ‘critical’ category.
Source: Ground Water Resource Assessment | cgwb

Formation of CGWA

The Central Ground Water Authority (CGWA) was established under the Environment (Protection) Act of 1986. This regulatory body is responsible for managing and controlling groundwater resources in India.

Largest Groundwater Irrigation Area

As per report of Food and Agriculture Organization (FAO) of UN, the countries with the largest extent of areas equipped for irrigation with groundwater, in absolute terms, are India (39 million ha), China (19 million ha) and the USA (17 million ha).

Q. Consider the following statements: 1. 36% of India’s districts are classified as ‘overexploited’ or ‘critical’ by the Central Ground Water Authority (CGWA). Read More »

Q. With reference to the history of India, consider the following pairs: Famous Place – Present State

Prelims 2020 GS Solution /

Q. With reference to the history of India, consider the following pairs: Famous Place – Present State

1. Bhilsa — Madhya Pradesh
2. Dwarasamudra — Maharashtra
3. Girinagar — Gujarat
4. Sthanesvara — Uttar Pradesh
Which of the pairs given above are correctly matched?
a) 1 and 3 only
b) 1 and 4 only
c) 2 and 3 only
d) 2 and 4 only
Correct Answer : a) 1 and 3 only

Question from UPSC Prelims 2020 GS Paper

Explanation:

Analysis of the Given Pairs

To determine the correct matches among the given pairs, let’s examine each one:

1. Bhilsa — Madhya Pradesh

Bhilsa, now known as Vidisha, is indeed in Madhya Pradesh. This place has historical significance and is known for its ancient monuments and archaeological heritage. So, this pair is correctly matched.

2. Dwarasamudra — Maharashtra

Dwarasamudra, the historical name for Halebidu, was the regal capital of the Hoysala Empire in the 12th century. It is actually located in Karnataka, not Maharashtra. Therefore, this pair is incorrectly matched.

3. Girinagar — Gujarat

Girinagar, also known as Girnar, is located in Gujarat. It is famous for its hill temples and ancient history. Thus, this pair is correctly matched.

4. Sthanesvara — Uttar Pradesh

Sthanesvara, historically known as Thanesar, is actually in Haryana, not Uttar Pradesh. It is a place of religious and historical importance. Therefore, this pair is incorrectly matched.

Given the analysis, the pairs that are correctly matched are:

  • Bhilsa — Madhya Pradesh
  • Girinagar — Gujarat

Therefore, the correct answer is a) 1 and 3 only.

Q. With reference to the history of India, consider the following pairs: Famous Place – Present State Read More »

Q.Siachen Glacier is situated to the

Prelims 2020 GS Solution /

Q.Siachen Glacier is situated to the

a) East of Aksai Chin
b) East of Leh
c) North of Gilgit
d) North of Nubra Valley
Correct Answer : d) North of Nubra Valley

Question from UPSC Prelims 2020 GS Paper

Explanation:

Location of Siachen Glacier

The Siachen Glacier, situated in the eastern Karakoram range in the Himalayas, is located to the north of the Nubra Valley. This makes option (d) “North of Nubra Valley” the correct answer. Here’s a detailed explanation:

a) East of Aksai Chin

This option is incorrect because Aksai Chin is located to the east of Ladakh, and the Siachen Glacier is not directly east of Aksai Chin.

b) East of Leh

This option is not accurate because Leh, the capital of Ladakh, is situated to the south of the Siachen Glacier.

c) North of Gilgit

Gilgit is part of the Gilgit-Baltistan region, which is administered by Pakistan. The Siachen Glacier is to the east of Gilgit, not directly north.

d) North of Nubra Valley

This is the correct answer. The Nubra Valley is located to the north of Leh and is known for its scenic beauty, including sand dunes and monasteries. The Siachen Glacier lies to the north of the Nubra Valley, making this the most accurate description of its location.

The Siachen Glacier is strategically significant and has been a point of military contention between India and Pakistan. It is known as the highest battlefield in the world, with both countries maintaining a military presence in the region despite the harsh climatic conditions.

Q.Siachen Glacier is situated to the Read More »