A group of college students are volunteering for help the homeless during spring break. They are putting the finishing touches o
n a house they built. Working alone, irina can paint a certain room in 4 hours. Paulo can paint the same room in 3 hours. write an equation that can be used to find how long it will take them working together to paint the room. how many hours will it take them to paint the room? A.12 hours
B.1.71 hours
C.0.14 hours
D.3.5 hours
Let us say
that x is the total amount of time it will take if they work together.
From the
given statement above, we know that the rate of Irina working alone is 1 job /
4 hours. While that of Paulo is 1 job / 3 hours. Where 1 job indicates to the
job of completely painting the room. So adding the two rates would result in 1
job / x hours. Therefore:
1 / 4 + 1 /
3 = 1 / x
Multiplying
both sides with 12 x:
(1 / 4 + 1 /
3 = 1 / x) 12 x
3 x + 4 x =
12
7 x = 12
x = 1.71
hours
So working
together, they can paint the room for 1.71 hours.
