Math Problem?

Question

Sally can paint a house in 4 hours. Johnny can paint the same house in 6 hours. How long would it take them to do together?

Explaination with answer please!!

Answer 1

2 hours and 24 minutes
If you multiply the speed of housepainting (houses/hour) by the number of hours, you get the number of houses, because the hours units cancel out.

John and Sally, when painting together, are painting for the same amount of time, let's call that T.

Then the total amount of houses that John paints in time T is T x 1/6 = T/6, because he paints 1 house in 6 hours alone.

The total amount that Sally paints is T x 1/4 = T/4 for the same reason.

So the total amount of houses they paint together is T/6 + T/4. But you know they together paint exactly one house in that time, so:

1 = T/6 + T/4.

If you now solve for T, you will have your time (expressed in hours,
so you may need to calculate the minutes from the fractional part
of the answer).
Set up the equation like this:
1/4 + 1/6 = 1/x
Multiply everything by the common denominator, 12x, you get:
3x + 2x = 12
5x = 12
x = 12/5 or 2.4 hours which is 2 hours 24 mins.

Answer 2

This is just a basic "job" problem. You'll get a lot of them if you are taking Alg. II! Set up a chart to organize your info..........

Sally 4 1/4
Jon 6 1/6
Both X 1/X

List each person or equip, time together or alone to complete the job, then as a fraction (denotes amount of the job that could be done in one hour).

Your equation...............

1/4 + 1/6= 1/x

Find the common denominator (Hint: it will be __X), combine like terms, then solve for X.

State soloution in a sentence!

Answer 3

I think 5 hours, (6+4)/2

Answer 4

i think that it would be 3 hours cause if u divid the numbers seperatly then add them it comes to 3

Answer 5

The answer is 1.5 hour because if you divied 6 and 4, it = 1.5

Answer 6

Do the math girl.. its 10!