Posted by Anonymous on .
Ben can complete 3 math problems in 20 minutes. If he continues working at the same rate, how long will it take Ben to complete 15 math problems?

math 
Ms. Sue,
15/3 = 5
It will take him 5 times 20 minutes to finish.
You could also set up a proportion. Cross multiply and solve for x.
3/20 = 15/x