Question

Alicia can paint a small room 21 hours faster than Nina aloneness 4 hours slower than Alicia and Nina together. How long will it take them to paint the room together? Express your answer in decimal form

Answer 1

11.413 Hours.

Explanation:

Alicia can paint a house in 21 hours; Which means in 1 hour she can paint 1/24 of the house.

Nina can paint the same house in (21+4) hours. Which means in 1 hour she can paint 1/25 of the house.

Together in 1 hour they can paint: 1/21 + 1/25 = 46/525 of the house.

Total Hours for painting the house together will be 525/46 = 11.413 Hours.