Question 1

# Three of the following four number-pairs are alike in a certain way and one is different. Identify the different one.

Solution

16:36 means $$4^2:6^2$$

25:49 means $$5^2:7^2$$

48:81 means $$4^2\times 3:9^2$$

64:100 means $$8^2:10^2$$

So, C is correct.