distance from A-B is 40 km.Mandy starts from A at 11 am and Jason starts from B at 1 pm.He walks at 5 km/h and gets to A at the same time as Mandy gets to B.How fast did Mandy walk?

Jason

r * t = 40
5t = 40
t = 8h.

Mandy
2h head start:
t = 8+2 = 10 h.
r * t = 40
r * 10 = 40
r = 4 km/h. = Mandy's speed.