Susan can type 10 pages in 5 minutes. Mary can type 5 pages in 10 minutes. Working together, how many pages can they type in 30 minutes?

Susan can type 10 pages in 5 minutes. Mary can type 5 pages in 10 minutes. Working together, how many pages can they type in 30 minutes?

A 15

B 20

C 25

D 65

Solution

Correct Answer: Option E

In one minute, Susan, does one page:

(5/10)=1/2

Mary, does one page:

(10/5)=2

So, both do :

Net-work: (2+1/2)=5/2

Thus ,

1 minute work done: 5/2

So, In 30-minutes : 30 * (5/2) = 75 pages