Problema Solution
two cars started from the same place at the same time but travelled in the opposite directions. after 9 hours they were 810 kilometers apart. if the speed of one car was 10 kilometers per hour slower than the other, what were their speeds per hour?
Answer provided by our tutors
let
v1 = the speed of the first car
v2 = the speed of the second car
d = 810 the distance between the cars
t = 9 hours the time of their travel
the speed of one car was 10 kilometers per hour slower than the other
v1 = v2 + 10
since speed = distance/time => distance = time*speed
v1t + v2t = d
9v1 + 9v2 = 810 divide both sides by 9
v1 + v2 = 90
by solving the system of equations
v1 = v2 + 10
v1 + v2 = 90
we find
v1 = 50 km/h
v2 = 40 km/h
click here to see the step by step solution of the system of equations
the speeds of the cars are 50 km/h and 40 km/h.