Problema Solution

P takes 3 hours more than Q to walk 30 km.but if P doubles his pace he is ahead of Q by 1/2 hours find their speed walking.

Answer provided by our tutors

let


d = 30 km the distance

t = the time that Q walks

t + 3 = the time that P walks


since speed = distance/time we have


v1 = d/(t + 3) is the speed of P

v2 = d/t is the speed of Q


if P doubles his pace he is ahead of Q by 1/2 hours


the new speed of P is: 2d/(t + 3) thus the time of the walk will be d/(2d/(t+3)) = (t+3)/2


(t+3)/2 = t - 1/2


by solving we find


t = 4 hr


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v1 = 30/(4 + 3)


v1 = 4.29 km/hr


v2 = 30/4


v2 = 7.5 km/hr


P's speed of walking is 4.29 km/hr.

Q's speed of walking is 7.5 km/hr.