SOLUTION: Pablo can paint a room in 2 hours, and his daughter Brenna can paint one in 8 hours. How long will it take them together to paint a room?

Question 715525: Pablo can paint a room in 2 hours, and his daughter Brenna can paint one in 8 hours. How long will it take them together to paint a room?

Answer by DrBeeee(684) (Show Source): You can put this solution on YOUR website!
Let P = time Pablo can paint one room
Let B = time Brenna can paint one room
Let T = time for both to paint one room
Use this simple formula
(1) T = (P*B)/(P + B)
Using given times we get
(2) T = (2*8)/(2 + 8) or
(3) T = 16/10 or
(4) T = 1.6
Answer: When they paint together they will take 1.6 hr. to paint one room.
Comment: The formula given by (1) can only be used for two people. If more than two the formula is the inverse of the sum of the inverses.
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