Posted by Josh on .
Josh and Mike live 13 miles apart. Yesterday Josh started to ride his bicycle toward Mike's house. When they met, Josh had ridden for twice the length of time as Mike and at 4/5 of Mike's rate. How many miles had Mike ridden when they met?
(a) 4
(b) 5
(c) 6
(d) 7
(e) 8

Math 
drwls,
Vj = 0.8 Vm
Josh rides for time t at speed Vj
Mike rides for time t/2 at speed Vm
Vm*t/2 + Vj*t = 13
Vm*t/2 + 0.8 Vm*t = 13
1.3 Vm t = 13
Vm t = 10
The distance Mike travelled is
(1/2) Vm t = 5 miles
You cannot solve for Vm and t separately, but you don't have to to get the answer.