Medium
16 : 64 :: 25 : ?
Explanation
Explanation
16=4 squared and 64=4 cubed, so the rule is: second number = first number raised to the power 1.5 (i.e., n x square root of n). Applying this to 25: 25 x 5 (square root of 25) = 125.
PRO TIP
Re-check your working by substituting the answer back into the original question.