The expression 555⁷⁷⁷+ 777⁵⁵⁵ is divisible by which of the following?

1. 2
2. 3
3. 37
Select the correct answer using the code given below:

Correct option is D

Solution:

​$$555^{777} + 777^{555}$$​​

=> (5 × 111)^{7 × 111} + (7 × 111)^{5 × 111}

=> 111⁵⁵⁵ (5⁷⁷⁷ × 111²²² + 7⁵⁵⁵)

111 is divisible by 3 and 37 both as 111 = 3 × 37,

Also, both the terms in bracket are odd so their sum will be even and hence divisible by 2.

∴ The correct answer is option d.