Question 895220
Kyle rode his bike for 12 miles.
 During the first third of the trip, he traveled on level ground at an average rate of 10 miles per hour.
 During the second third of the trip, he traveled uphill at an average rate of 6 miles per hour.
 During his last third of the distance, kyle traveled downhill at an average rate of 15 miles per hour.
 How long did kyle's 12-mile bike trip take?
:
4 mi is 1/3 of the trip, so we have a simple time equation;
time = dist/speed
:
t = {{{4/10}}} + {{{4/6}}} + {{{4/15}}}
convert of common denominator, 30
t = {{{12/30}}} + {{{20/30}}} + {{{8/30}}}
t = {{{40/30}}} = {{{4/3}}} hr = 1 hr 20 min