The sum of factors of 1520 except the unity is :

Options

A. 3720
B. 2730
C. 2370
D. none of these

Answer

D

Explanation

Since 2520 = `2^4xx5^1xx19^1`
`therefore` Sim of all factors of 1520 = `((2^5-1)(5^2-1)(19^2-1))/(2-1)(5-1)(19-1) = (31xx24xx360)/(1xx4xx18) = 3720`
But since unity is to be excluded. `therefore` The net sum of the factors = 3719