A person travels from A to B at a speed of 75 kin/hour in a car and returns from B to A by reducing his speed by 15 km/hour. If the total time taken is 3 hours, then the distance between A and B, in kilometers, is

Solution:

Let,The distance between A-B be $$d$$.

While going from A to B Speed = 75 kmph

Time = $$\ \ \frac{\ Dis\tan ce}{Speed}$$ = $$\ \ \frac{\ d}{75}$$ hours

While going from B to A Speed = 75 kmph

Time = $$\ \ \frac{\ Dis\tan ce}{Speed}$$ = $$\ \ \frac{\ d}{75 - 15}$$ = $$\ \ \frac{\ d}{60}$$ hours

Total time = 3 hours

=> $$\ \ \frac{\ d}{75}$$ + $$\ \ \frac{\ d}{60}$$ = 3

$$\ \frac{\ d}{75}+\frac{d}{60\ }\ =\ 3$$

$$\ \frac{\ 4d\ +5d}{300}\ =\ 3$$

$$\ \frac{\ 9d}{300}\ =\ 3$$

$$\ \ d=\ 100\ km$$ Answer