Question 148362
Distance(d) equals Rate(r) times Time(t) or d=rt;  r=d/t and t=d/r
Let r=walking rate
Then 4r=cycling rate

Time spent walking=5/r
Time spent cycling=40/4r=10/r

Now we are told that the sum of the above times is 5 hours, so:

5/r + 10/r=5  multiply each term by r
5+10=5r
15=5r    divide each side by 5
r=3 mph------------------walking rate
4r=4*3=12 mph----------------cycling rate

ck
40/12 + 5/3=5
40/12+20/12=5
60/12=5
5=5

Hope this helps------ptaylor