WBCS Preliminary Examination 2023 — General Studies · Question 80 of 200

Answer: (A) 20

Work from the innermost brackets. $7*2$: since $7>2$, it is $7-2=5$. Then $5*5$: the numbers are equal, so it is $2\times5=10$. Next $5*7$: since $5<7$, it is $5+7=12$. Then $12*2$: since $12>2$, it is $12-2=10$. Adding the two parts, $10+10=20$. The trap lies in the middle step: after the first bracket becomes 5, the operation $5*5$ must use the "equal" rule ($2x$), not addition or subtraction.