Question

Sally can paint a room in 3 hours while it takes Steve 9 hours to paint the same room. How long would it take them to paint the room if worked together?

Answer 1

Answer:

$2 \frac{1}{4}$

Step-by-step explanation:

Okay, so- The first thing I did was see how much they got done per hour. Like this:

Sally  ⇒

3 hours = 1 room

1 hour = 1/3 of the room

Steve ⇒

9 hours = 1 room

1 hour = 1/9 of the room

Sally + Steve ⇒

1 hour = 1/3 + 1/9 = 3/9 + 1/9 = 4/9

So, they get 4/9 of a room done in 1 hour.

Number of hours needed ⇒

1 ÷ 4/9 = 2 1/4  

Answer: They need 2 1/4 hours to paint the room.