Question

A man can work at a speed of 6 km per hour and jog at a speed of 10 km per hour .He covered a distance of 9 km in 1 hour partly by walking and partly by jogging .Find for how much time he walked and how much distance?

Answer 1

let
v1 = 6 km/h the walking speed

v2 = 10 km/h the jogging speed

t1 = the he walked

t2 = the time he jogged

d = 9 km the total distance
t1 + t2 = 1
since speed = distance/time => distance = speed*time
v1*t1 + v2*t2 = d
6t1 + 10t2 = 9
by solving the system of equations
t1 + t2 = 1
6t1 + 10t2 = 9
we find
t1 = 0.25 h = 0.25*60 min = 15 min
t2 = 0.75 h = 0.75*60 min = 45 min

he walked 15 min.
the distance he walked is equal to v1*t1 = 6*0.25 = 1.5 km.