Math Word Problem. Need Help!?

Question

Having trouble doing these type of problems.

If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together?

Please, tell me how to do problem like these and help me solve this problem. Please show your work so I can see where your coming from.

Thanks

Answer 1

Sally can paint 1 house in 4 hours.
She can therefore paint 1/4 of a house every hour.
John can paint 1 house in 6 hours.
He can therefore paint 1/6 of a house every hour.
Working together, they can paint:
1/4 + 1/6 = (3 + 2) / 12 = 5 / 12 of a house every hour.
They can therefore paint 1 house in:
12 / 5 hr
= 2 2/5 hr
= 2hr 2*60/5 min
= 2hr 24min.

Answer 2

This is not as easy as it sounds. sally can paint 1/4 of the house in 1 hour whilst John can only paint 1/6th. So in 1 hour between them they paint:

1/4 + 1/6 = 3/12 + 2/12 = 5/12
In 2 hours they would paint 2 x 5/12 = 10/12
leaving 2/12
That leaves 2/12 and they can paint 5/12 in 1 hour so the last 2/12 would take 2/5 x 60 minutes = 24 minutes
The whole job is 2 hours and 24 minutes.

Answer 3

1/4 + 1/6 = 5/12

1/ (5/12) = 12/5 = 2.4 hrs

Sally will do 1/4 of the work in an hour and John will do 1/6. Together they will do 5/12 of the work. And if in one hour they complete 5/12 of the work, then to complete 12/12 of the work they will need 2.4 hrs. I hope this helps.

Answer 4

its the simple formula of (A x B)/(A + B) which is (4 x 6)/(4 + 6) which equals 24/10 or 12/5. That in turn equals 2.4 hours or 2 hours and 24 minutes.

Answer 5

2 hours and 24 minutes..

Sally=4 hours
John=6 hours

Together

1/4 +1/6= 1/h

h=2.24

Answer 6

5 hours....take the average 4+6=10 then divide 10 by 2 to get the average