Sally can paint a house in 4 hrs; John can paint it in 6 hrs. How long will it take them to paint it together?

Answer 1

Sally finishes 1/4 of the job in an hour.
John finishes 1/6 of the job in an hour.

Together they finish 1/4 + 1/6 of the job in an hour...

You need to find a common denominator:
1/4 + 1/6

In this case it is 12, so multiply the first fraction by 3/3 and the second by 2/2:
3/12 + 2/12

Add them together:
5/12

So they can do 5/12 of the job in 1 hour.

The amount of time to do 1 complete job is the reciprocal.
5/12 * x = 1
x = 12/5

Thus, together they take 12/5 hours which is:
2 2/5 hours or 2.4 hours

Converting to minutes:
(2/5 * 60 = 24 minutes)

That means they would take 2 hours 24 minutes working together.

Answer 2

Ok so Sally can paint 1/4 house per and John can paint 1/6 house per hour So together they can paint 1/4 + 1/6 house in one hour, or 3/12 + 2/12= 5/12 house per hour So they can paint the whole house in 12/5 hour or 2 2/5 hour or 1 hour 24 minutes

Answer 3

Each hour, Sally does 1/4 of the house and John does 1/6

so if x = the time in hours it takes them both to finish:

1/4 x + 1/6 x = 1.00 (one house)

3/12 x + 2/12 x = 1

5/12 x = 1

x = 12/5 hours, or 2 hours and 24 minutes

Answer 4

Sally = x/4 hours

John = x/6 hours

Together = 1 = team work

x/4 + x/6 = 1

Next: Solve for x

After doing the algebra, I get:

x = 2.4 hours.

Guido

Answer 5

2 hrs

Answer 6

2hrs 24mins

Answer 7

Could you please retype the question taking into account the effects of special relativity?

Answer 8

u won't learn if you don't do ur homework by ur self