Question 98432
Distance(d) equals rate(r) times time(t) or d=rt; t=d/r and r=d/t

Let r=Tom's rate of speed walking
Then 5r=his rate of speed biking (assuming Tom's estimate is correct)

distance walking = distance riding

Now we are told that the time walking plus time riding equals 5hr 24min.

Time walking=7/r
Time riding=7/5r

So our equation to solve is:

7/r+7/5r=5hr 24min or 27/5 hr  multiply each term by 5r

35+7=27r  combine like terms

42=27r  divide both sides by 27

r=1.5555555556 mph------------------Tom's rate of speed walking

5r=5*1.56=7.777777778 mph--------------Tom's rate of speed biking


CK
7/(1.5555555556)+7/(7.777777778)=5.4
4.49999999+0.8999999=5.4
5.39999999~5.4


Hope this helps----ptaylor