Question 374395
Blaise rode his bike to his friend Elroy's house, which was 15 miles away.
 After he had been riding for half an hour, he go a flat tire.
 He walked his bike the rest of the way. The total trip took him 3 hours. 
If his walking rate was one-fourth as fast as his riding rate, how fast did he ride?
:
Let w = his walking rate
then
4w = his riding rate
:
Given that he rode .5 hrs, then he walked: 3 - .5 = 2.5 hrs
:
Write a distance equation: Dist = time * speed
2.5w + .5(4w) = 15
:
2.5w + 2w = 15
:
4.5w = 15
w = {{{15/4.5}}}
w = 3{{{1/3}}} mph is his walking speed
then
4(3{{{1/3}}}) = 13{{{1/3}}} mph is his riding speed
:
:
Check solution using decimals
2.5(3.33) + .5(13.33) = 14.99 ~ 15, confirms our solutions