Problema Solution
Kathy bicycles 4 km/h faster than Dennis. In the same time it takes Dennis to bicycle 42km, Kathy can bicycle 54 km. How fast does each bicyclist travel?
Answer provided by our tutors
let kathy speed is x
and dennis is y
x= y+4
let time is t
xt=54
and yt=42
yt=42/54 * 54= xt* 14/18= xt*7/9
=> y= x*7/9
=> y= (y+4)* 7/9
= 9y= 7y+28
=> 2y=28
=> y=14km/h
thus x=14+4=18km/h