Question

It takes 3 1/3 kilometers of thread to make 3 1/2 boxes of shirts. How many kilometers of thread will it take to make 6 boxes?

Answer 1

5 5/7 km

Explanation:

We assume the length of thread is proportional to the number of boxes of shirts. If L is the thread length required, then that assumption means

... L/(6 boxes) = (3 1/3 km)/(3 1/2 boxes)

Multiplying the equation by (6 boxes), we get

... L = (3 1/3 km)(6/(3 1/2)) = (10/3 km)(6/(7/2))

... = (10/3 km)(12/7) = 40/7 km = 5 5/7 km