Question

Which of the following numbers will completely divide
2⁶¹ + 2⁶² + 2⁶³ + 2⁶⁴?
​(a)100
(b) 10
​(c)27
​(d)17

Answer 1

Dear Student,

(2⁶¹ + 2⁶² + 2⁶³ + 2⁶⁴) = 2⁶¹ x (1 + 2 + 2² + 2³) = 2⁶¹ x 15

= 2⁶⁰ x (2 x 15)

= (2⁶⁰ x 30), which is divisible by 10.

Regards