Question 259807
A man rides a bike a straight distance at a speed of 10 miles per hour.
 He came back the same way, traveling the same distance at a speed of 20 miles per hours. 
What was the man's total number of miles for the trip back and forth if his total traveling time was one hour?? 
:
Let d = no. of miles one-way
:
Write a time equation: Time = dist/speed
:
Time there + time back = 1 hr
{{{d/10}}} + {{{d/20}}} = 1
Multiply equation by 20, get rid of the denominators, results:
2d + d = 20
3d = 20 
 d = {{{20/3}}}
 d = 6{{{2/3}}} (miles one way)
Therefore
2(6{{{2/3}}}) = 13{{{1/3}}} total miles
:
:
Check on a calc;
6.67/10 + 6.67/20 = 
.667 + .333 = 1