Question

Two computers working together can finish a search in 30 seconds. One of these computers can finish in 50 seconds. How long would it take the second computer to finish the same search if it were working alone?

Answer 1

Two computers take 30 seconds, so the time for both computers is 1/30 per second.

One computer takes 50 seconds so it is 1/50 per second.

2nd computer would be the speed of both computers minus the speed of the first computer: 1/30 - 1/50

Find common denominator: 30 *50 = 150
1/30 = 5/150
1/50 = 3/150

Subtract: 5/150 - 3/150 = 2/150 = 1/75

It would take the second computer 75 seconds