Question

. If a person had walked 1 km/hr faster, he would have taken 15 minutes less to walk 3 km.Find the original rate of his walking.

Answer 1

Distance= 3 km

Original Speed = X km/hr

Original time = T hr

When speed is X km/hr :-

D=S×T

X = 3/ T

When speed is X+1 km/hr :-

3 =( X+1) × (T-15/60)

3 = (3/T + 1) × (T - 1/4)

(3+T) × ( 4T-1)

3 = ------- ---------

T 4

4T×3 = 12T - 3 + 4Tsq. - 1

12T = 12T - 3 + 4Tsq. - 1

3+1 = 4Tsq.

T = 1 hr

X = D/T

X = 3 / 1 = 3 km/hr.