Then f(p) would be the amount that the house was sold for after being on the market for "p" days. Applying that p = 150; then f(150) means that the house was sold for $150,000 after being on the market for an average of 150 days.
First you woyld find how many hours total he worked. Then take the number of hours and multiply by the pay earned per hour. They would make $360 per week.