Math with Mrs. Sarah

(Haese, Motion Problems, MYP4)

First recall these 3 equations

Joe can run twice as fast as Pete. They start at the same point and run in opposite directions for 40 minutes. The distance between them is now 16 km. How fast does Joe run?

A car leaves a country town at 60 km per hour. Two hours later, a second car leaves the town; it catches the first car after 5 more hours. Find the speed of the second car.

A boy cycles from his house to a friend’s house at 20 km h⁻¹ and home again at 25 km h⁻¹. If his round trip takes 9 of an hour, how far is it to his friend’s house?

A motor cyclist makes a trip of 500 km. If he had increased his speed by 10 km h⁻¹, he could have covered 600 km in the same time. What was his original speed?

Normally I drive to work at 60 km h⁻¹. If I drive at km h⁻¹ I cut 8 minutes off my time for the trip. What distance do I travel?

My motor boat normally travels at 24 km h⁻¹ in still water. One day I travelled 36 km against a constant current in a river. If I had travelled with the current, I would have travelled 48 km in the same time. How fast was the current?