Q. A number is mistakenly divided by 4 instead of multiplying by 4. What is the percentage change in the result due to this mistake?

Explanation : 

Number is mistakenly divided by 4 instead of multiplying by 4

1) Our original number is 100.

2) The correct operation should be: 100 * 4 = 400

3) The mistaken operation is: 100 ÷ 4 = 25

4) Now, let’s calculate the percentage change:
(Mistaken result – Correct result) / Correct result * 100
= (25 – 400) / 400 * 100
= -375 / 400 * 100
= -0.9375 * 100
= -93.75%

5) The negative sign indicates a decrease. The question asks for the percentage change, which is the absolute value.

Therefore, the percentage change is 93.75%.