Question

The sum of the digits of a large number is 81. Using the divisibility rules, by which number or numbers is that large number divisible?

A. Only 3
B. 3 and 6
C. 3 and 9
D. 3, 6, and 9

Answer 1

C. 3 and 9

Explanation:

81 divide by 3 = 27

81 divide by 9 = 9

Answer 2

The sum of the digits is 81

sum the digits again and get 9

Therefore, as 9 is only divisible by 9 and 3 the answer is 'C'