27^5+3^{13} is divisible by

  1. A. 8
  2. B. 10
  3. C. 12
  4. D. 21

Correct Answer: B. 10

Explanation

Rewrite 27^5 as (3^3)^5 = 3^{15}. The expression becomes 3^{15} + 3^{13} = 3^{13}(3^2 + 1) = 3^{13}(10). This is clearly a multiple of 10.

Related questions on Arithmetic

Practice more CDS Elementary Mathematics questions