Question 357051
eric plans to compete in a triathlon. he can average 2 miles per hour in the
 1/4-mile swim and 6 miles per hour in the 3-mile run. his goal is to finish
 the triathlon in 2 hours. 
to accomplish his goal what must his average speed, in miles per hour, be for
 the 15-mile bicycle ride?
:
Let s = his average biking speed
:
Write a time equation: time = dist/speed
:
{{{.25/2}}} + {{{3/6}}} + {{{15/s}}} = 2
Multiply by 6s, results:
3s(.25) + 3s + 6(15) = 2(6s)
:
.75s + 3s + 90 + 12s
3.75s - 12s = -90
-8.25s = -90
s = {{{(-90)/(-8.25)}}}
s = +10.91 mph biking speed, the fraction would be {{{120/11}}}