I travelled from A to B at 100km/h. This trip would take me 3 hours more at 80km/h. How far is it from A to B?

Question

I travelled from A to B at 100km/h. This trip would take me 3 hours more at 80km/h. How far is it from A to B?

Answer 1

The distance formula is distance = rate*time or d=rt

 

Driving at 100 km/hr let the time be t

Driving at 80 km/hr the time is t+3

 

d = 100t

d = 80(t+3)

 

Since the distance driven is the same we can set these equal to each other.

 

100t = 80(t+3)        distribute the 80 through the parenthesis

100t = 80t + 240     subtract 80t from both sides

20t = 240                divide both sides by 20

t = 12 hours

 

It takes 12 hours to make the drive at 100 km/hr and 15 hours to do it at 80 km/hr

 

the distance is 100t = 100(12) = 1,200 km