Question

if lcm of two prime numbers a and b (a>b) is 667 then the value of 7b-5a is:

Answer 1

LCM of two prime numbers is always product of both the numbers.

So. in this case 667 = a * b

Factors of 667 are 23 and 29

Since a > b, a = 29 and b = 23

7b = 23 * 7 = 161

5a = 29 * 5 = 145

7b - 5a = 161 -145 = 16

So, answer is 16