Problema Solution
Li and Hector work as independent housepainters. On average, Hector can paint a house 17 hours faster than Li can. During a busy part of the year, they decide to work together, and they can, on average, paint each house in 23 1/3 hours. What is the average amount of time Li spends painting each house when he works alone?
Answer provided by our tutors
Let 'l' and 'h' stand for the rates of Li and Hector. We will use the general equation (number of houses painted)=(rate)*(time). We can write:
Hector:
1=h(t-17)
Li:
1=lt
together:
1=(l+h)(70/3)
Solving for 'h' and 'l', we get:
h= 3/119 houses/hrs
l= 3/170 houses/hrs
Therefore, on average, Li spends 170/3 hours painting each house. This is equal to 56 2/3 hours.