Question

Complete the series. 9 = 4, 21 = 9, 22 = 9, 24 = 10, 8 = 5, 7 = 5, 99 = 10, 100 = 7, 16 = ?, 17 =?

Answer 1

 16 = 7 and 17 = 9 [The number of letters in the spelling of 16 (sixteen) is 7 and that of 17 (seventeen) is 9]