SOLUTION: A race car is traveling 40 km/hour faster than another on a race track. While the faster car travels 70 km, the second travels 60 km. find the speed of the faster car in km/hr.
Algebra ->
Customizable Word Problem Solvers
-> Misc
-> SOLUTION: A race car is traveling 40 km/hour faster than another on a race track. While the faster car travels 70 km, the second travels 60 km. find the speed of the faster car in km/hr.
Log On
Question 770019: A race car is traveling 40 km/hour faster than another on a race track. While the faster car travels 70 km, the second travels 60 km. find the speed of the faster car in km/hr. Answer by josgarithmetic(39617) (Show Source):
You can put this solution on YOUR website! One of the keys is , "While the faster,... the second...". The amount of time is the same time interval. Call the time quantity, x hours.
Make expressions for x for each car using r*t=d:
CAR_________RATE_________TIME__________DISTANCE
Slow________r____________60/r_____________60
Fast_______r+40__________70/(r+40)_____________70
The time quantities being equal, we just show the equation: and solve for r.
... and of course, r+40.
(