Distance Rate Time problem One morning, Ryan remembered lending a friend a bicycle. After breakfast, Ryan
walked over to the friend’s house at 3 miles per hour, and rode the bike back home at 7
miles per hour, using the same route both ways. The round trip took 1.75 hours. What
distance did Ryan walk?
HINT:

Let the distance between the friend’s house from Ryan's is $d$ miles

As we know speed $\displaystyle =\frac{\text{distance}}{\text{time}}\implies $ time $\displaystyle =\frac{\text{distance}}{\text{speed}}$

So, to go to the friend’s house, he took $\frac d3$ hours

While returning he took $\frac d7$ hours

So,  $\frac d3+\frac d7=1.75$
As given total time taken is 1.75 hrs
So assume total distance is d than
1.75=d/3+d/7

1.75=10d/21
d=3.675miles ans walking distance