Question
This question came from my reader's comment
Distance between Town X and Y is 100km.
At 07:00, Sam left Town X and cycled towards Y.
Ann left Town X and cycled towards Y at 07:30.
Ann's cycling speed was 4 km/h faster than Sam. At 10:00, Ann caught up with Samuel. When Ann was 28 km from town Y, she stopped to wait for Samuel.
(a) How far was Samuel from Ann when she stopped to wait for him?
(b) How many minutes did Ann wait for Samuel?
Answer
First answer is kind of model-based, but a bit too long. I prefer the second method which uses a triangle to represent distance/speed/time relationship. Although there is little bit of algebra, I think the kid should be able to handle it.
