Question

If the sum of three consecutive multiples of 9 is 108, then the third multiple is :

• A. 36
• B. 45
• C. 55
• D. 65

Answer 1

The correct option is B

45

If x is a multiple of 9, then the next two multiples are x + 9 and x + 18.

So three consecutive multiples of 9 are x, x + 9, x + 18

x + (x + 9) + (x + 18) = 108

3x + 27 = 108

x = $\frac{108-27}{3}$ = $\frac{81}{3}$ = 27

So, first multiple is 27
Second multiple is 27 + 9 = 36
Third multiple is 27 + 18 = 45.