WBCS 2021 Mains (General Studies Paper-IV) Prev. Yr. Paper (24-May-2022)

If '+' stands for division, '$÷$ ' stands for multiplication, '$\times$ ' stands for subtraction and '-' stands for addition, which of the following equations is correct?

The radius of a spherical gas balloon increases from $7\text{cm}$ to $21\text{cm}$ as air is being pumped into it. The ratio of the surface areas of the balloon in the two cases is:

Direction: Study the following info carefully:
Input: $983106726359361284$
Step 1: $983136726359061284$
Step 2: $843136726359061298$
Step 3: $843136637259061298$

New Input: $593612849831067263$
Which of the following is the third step for this input?

The difference between the squares of two consecutive even integers is always divisible by:

If the edge of a cube is increased by $25\%$, then the percentage increase in its surface area is: