Question

hannah can paint a room in 9 hours. destiny can paint the same room in 15 hours. if they work together, how long does it take them to paint the room?

Answer 1

5 hours 38 minutes

Explanation:

Let's call Hannah H, and Destiny D.

9H = 1 (think of 1 as 100% of the job done). call this equation '1'.

15D = 1 call this '2'

multiply '1' by 5:

45H = 5

multiply '2' by 3:

45D = 3

add both up:

45H + 45D = 5 + 3

45H + 45D = 8

45(H + D) = 8.

H + D is Hannah and Destiny working together. we want to make the right side of equation 1.

divide both sides by 8:

(45/8) (H + D) = 1

so it will take both of them 45/8 ≈ 5 hours 38 minutes to paint it together