Question

Jonathan can type a 20 page document in 40 minutes, Susan can type it in 30 minutes, and Jack can type it in 24 minutes. Working together, how much time will it take them to type the same document?

Answer 1

J=20/40=1/2per min
S=20/30=2/3per min
JK=20/24=5/6per min

In one min together 1/2+2/3+5/6=12/6=2 pages.

For 20 pages=20/2=10 it would take 10 mins

Answer 2

Answer:

It takes 10 minutes for Jonathan, Susan and jack to type the document

Step-by-step explanation:

Given:

Time Taken by Jonathan to type 20 page document=40 minutes

Time Taken by Susan to type 20 page document=30 minutes

Time Taken by Jack to type 20 page document= 24 minutes

To Find:

Total time taken if all three type together=?

Solution:

Number of pages Jonathan can type in 1 min = $\frac{20}{40}$= $\frac{1}{2}$ pages

Similarly, Number of pages Susan can type in 1 mi =  $\frac{20}{30}$= $\frac{2}{3}$ pages

Similarly, Number of pages Jack can type in 1 mi =  $\frac{20}{24}$= $\frac{5}{6}$  pages

So, if they all work together then

no. Of pages they can type in 1 min = $\frac{1}{2}$+ $\frac{2}{3}$+ $\frac{5}{6}$=2 pages

no. Of pages they can type in 1 min =0.5+0.6+0.8

no. Of pages they can type in 1 min = 2 pages

So, they can type 20 pages in = $\frac{20}{2}$=10 min