need help

[flew62999]

John leaves his house at 7:00 a.m. His sister, Mary leaves the house at 8:30 a.m. and tries to catch up with John. She is walking 2 km/h faster than him on the same route in the same direction. If they both kept on the same route, Mary could reach John 3 hours after she left. Find John and Mary’s speed.

 

[jacket81]

problem

Letting x by john speed, then wouldn't mary's speed then be x+2?
But john already had a hour and half head start, or 1.5x.
So, if she caught up with him, wouldn't equation be (x+2)3 = 1.5x+3x?

 

[stapel]

...wouldn't equation be (x+2)3 = 1.5x+3x?

It sounds like you're not sure of yourself, but your set-up and reasoning are exactly correct.

Good work! :wink:

Eliz.