16 : 64 :: 40 : ?
MPPSC State Service - 2018,
Answer: C
The missing number is 400.
The rule linking 16 and 64 is: square the number and divide by 4. 162 = 256 and 256/4 = 64. Applying the same rule to 40: 402 = 1600, and 1600/4 = 400.
A simple multiplication by 4 would give 160, which is not offered, so the pair must be read through the squaring rule. 4 and 40 make the second term smaller than or equal to the first, and 4000 overshoots by a factor of ten.
Please log in or register to report this question.