Question

If a Student can walk 1 km/h faster. he could have taken 15 min less to walk 3km. find the rate at which he was walking

Answer 1

ok

Distance travelled = 3 km

Let the original rate of walking be x kmph

Time taken to travel = distance / speed

= 3/x

Given speed of person is increased by 1 kmph

Hence the new speed becomes (x + 1) kmph

Time taken to travel with increased speed = 3/(x +1)

Time = 15 min = 15/60 = 1/4 hours

Hence (3/x) - [3/(x + 1)] = (1/4)

3[x + 1 - 1]/x(x+1) = (1/4)

3x / x(x + 1) = 1/4

3/(x + 1) = 1/4

12 = x + 1

Hence x = 11

Thus the original rate of walking is 11 kmph.