One maid can clean the house three times faster than another. working together they can clean the entire house in 3 hours. How long would it take the faster maid cleaning alone?
Help!
We can measure house-cleaning speed with the unit: houses/hour. (We consider the house in question to be the "standard" house.)
Let s be the slower speed, and f be the faster speed.
Then s+f = 1/3.
We also know that f = 3s.
So s + 3s = 1/3.
s = 1/12 houses/hour.
f = 3s = 3/12 = 1/4 houses/hour.
So it would take the faster maid 4 hours.