Posted by anoynomous on .
a man travels some distance at a speed of 12km/hr and returns at 9km/hr .if the total time taken by him is 2hrs 20 min ,find the distance.

mathsequation 
Reiny,
time for first part = d/12
time for return = d/9
d/12 + d/9 = 7/3
times 36
3d + 4d = 84
7d = 84
d = 12
the distance was 12 km