The logic follows here is : For, 19 : 85 19 : 19 x 5 - 5 x 2 Similarly, 21 : ? 21 : 21 x 5 - 5 x 2 21 : 105 - 10 21 : 95 '95' is related to the third number in the same way as the second number is related to the first number. Hence, the correct answer is "95".