Q. Three Statements S1, S2 and S3 are given below followed by a Question:
S1: C is younger than D, but older than A and B. S2: D is the oldest. S3: A is older than B.
Question: Who among A, B, C and D is the youngest? Which one of the following is correct in respect of the above Statements and the Question? (a) S1 alone is sufficient to answer the Question. (b) S1 and S2 together are sufficient to answer the Question. (c) S2 and S3 together are sufficient to answer the Question. (d) S1 and S3 together are sufficient to answer the Question. Correct Answer: (d) S1 and S3 together are sufficient to answer the Question.
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
C is younger than D
From statement S1 we know that C is younger than D but older than A and B. So the order of their ages is: D > C > A and B.
From statement S3 we know that A is older than B. Combining this information with statement S1, we get the order of their ages as: D > C > A > B.
So from statements S1 and S3 together, we can conclude that B is the youngest among A, B, C and D
Q. Which one of the following will have minimum change in its value if s is added to both numerator and the denominator of the fractions 2/3, 3/4, 4/5 and 5/6?
ANALYSIS: 1. When s becomes very large: – The numerator terms (2,3,4,5) become negligible – The denominator terms (3,4,5,6) become negligible – All fractions approach s/s = 1
Finding the least four-digit number with remainder 2 when divided by 3, 4, 5, and 6
STEP 1: Find the LCM of 3, 4, 5, and 6 – First, we need the least common multiple (LCM) of 3, 4, 5, and 6 – The LCM of these numbers is 60
STEP 2: Find the smallest four-digit number divisible by LCM – We need to find the smallest four-digit number divisible by 60 – The smallest four-digit number divisible by 60 is 1020
STEP 3: Add remainder – Since we want remainder 2 when divided by 3, 4, 5, and 6 – We add 2 to our number: 1020 + 2 = 1022
ANSWER: 1022 is the least four-digit number that leaves remainder 2 when divided by 3, 4, 5, and 6
For which period was the natural growth rate maximum ?
The natural growth rate is calculated by subtracting the death rate from the birth rate. From the data you provided, we can calculate the natural growth rates for each period:
1911-1921: 48.1 – 35.5 = 12.6
1921-1931: 46.4 – 36.3 = 10.1
1931-1941: 45.2 – 31.2 = 14
1941-1951: 39.9 – 27.4 = 12.5
1951-1961: 41.7 – 22.8 = 18.9
1961-1971: 41.1 – 18.9 = 22.2
1971-1981: 37.1 -14 .8 = 22.3
The maximum natural growth rate was 22.3 during the period 1971-1981.
Let’s solve this problem step by step. A negative exponent means that the base is inverted and the exponent becomes positive. For example, (1/2)^-6 can be written as (2/1)^6.
Using this logic, we can rewrite all the options as follows: (a) (1/2)^-6 = (2/1)^6 = 64 (b) (1/4)^-3 = (4/1)^3 = 64 (c) (1/3)^-4 = (3/1)^4 = 81 (d) (1/6)^-2 = (6/1)^2 = 36
Q. A shop owner offers the following discount options on an article to a customer:
1. Successive discounts or 10% and 20%, and then pay a service tax of 10% 2. Successive discounts of 20% and 10%, and then pay a service tax of 10% 3. Pay a service tax or 10% first, then successive discounts of 20% and 10%
Which one of the following is correct? (a) 1 only is the best option for the customer. (b) 2 only is the best option for the customer. (c) 3 only is the best option for the customer. (d) All the options are equally good for the customer. Correct Answer: (d) All the options are equally good for the customer.
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
A shop owner offers the following …
Let’s calculate the effective discount for each option, assuming the original price of the article is P.
All three options result in the customer paying the same final price, which is 79.2% of the original price (0.792P). So, all options are equivalent in terms of the final price for the customer.