Question 873541
While training for an iron man competition,tony bikes for 60 miles and runs for 15 miles.
 If his biking speed is 8 times his running speed and it takes 5 hours to complete the training.
:
Let s = his running speed
then
8s = his biking speed
:
Write a time equation: time = dist/speed
;
bike time + run time = 5 hrs
{{{60/(8s)}}} + {{{15/s}}} = 5
Multiply thru by 8s, cancel the denominators
60 + 8(15) = 5(8s)
180 = 40s
s = 180/40
s = 4.5 mph is his running speed
then
8*4.5 = 36 mph is his biking speed
"how long did he spend on his bike?"
60/36 = 1{{{2/3}}} hrs on the bike
:
:
See if that checks out, find the total time from the bike and run times:
{{{60/36}}} + {{{15/4.5}}} = 
1.67 + 3.33 = 5 hrs