Question

A contractor charges $ 1,200 for 100 square feet of roofing installed. At this rate, how much does it cost to have 1,100 square feet installed

Answer 1

For this problem we can use a proportion to solve.

Set up the proportion.

$\frac{1200}{100} = \frac{p}{1100}$

Cross multiply.

$1200 * 1100 = 100 * p\\1320000 = 100p$

Divide.

$\frac{1320000}{100} = \frac{100}{100}p\\13200 = p$

So, it would cost $13,200 to have a 1,100 square foot roof installed.