Question

Marcus can walk 1 mile to the library in the same time he can bicycle 2.5 miles to the sporting goods store. His speed on the bicycle is 6 mi/h faster than his walking speed. What is his speed walking?

Answer 1

Let
x------> speed on the bicycle
y------> speed walking

we know that
x=6+y------> equation 1
speed=distance /time-------> time=distance/speed
1/y=2.5/x-------> y=x/2.5------> x=2.5y-------> equation 2

equals 1 and 2
6+y=2.5y-----> 2.5y-y=6------> 1.5y=6-----> y=6/1.5-----> y=4 mi/h
x=6+y-----> x=6+4-----> x=10 mi/h

the answer is
the speed walking is 4 mi/h