Question 394157
Justin can jog to work in 3/4 of an hour.
When he rides his bike, it takes him 1/3 of an hour. 
If he rides 12 miles per hour faster than he jogs, how far away is his work?
:
Let s = his jogging speed
then
(s+12) = his biking speed
:
Write a distance equation
jog dist = bike dist
{{{3/4}}}s + {{{1/3}}}(s+12)
multiply by 12 to get rid of the fractions; results:
3(3)s = 4(s+12)
9s = 4s + 48
9s - 4s = 48
5s = 48
s = {{{48/5}}}
s = 9.6 mph is the jogging speed
then
(9.6+12) = 21.6 mph is the biking speed
:
Find the distance;
{{{3/4}}}*9.6 = 7.2 mi
:
Check the distance, biking;
{{{1/3}}}*21.6 = 7.2 mi