Question

A person covers a certain distance with certain speed, if he increases his speed by 16 km/hr. then he will be 3 hrs. before. If decreases his speed by 16 km/hr the will be 6 hr. late. Find his original speed.​

Answer 1

The original speed of the person

= 48 Km/hr

Let the original speed of the person be equal to x Km/hr.

Let the time taken = t hrs.

Distance travelled = x × t

When speed is increased by 16 Km/hr -

speed = x + 16

time taken = t-3

Distance travelled = (x+16) × (t-3)

=> x × t = (x+16) × (t-3)

=> xt = xt +16t -3x-48

=> 16t - 3x -48 = 0 ----(1)

When speed is decreased by 16 Km/hr -

speed = x - 16

time taken = t+6

Distance travelled = (x-16) × (t+6)

=> x × t = (x-16) × (t+6)

=> xt = xt -16t +6x-96

=> 16t -6x +96 = 0 ----(2)

Solving the equations (1) and (2) to find the values of x and t.

x = 48 Km/hr

t = 12 hours