Respuesta :
Answer:the speed of the faster car is 75 miles per hour
Step-by-step explanation:
Initially, the distance between the two cars before they travelled towards each other is 420 miles.
Let x represent the speed of the slower car.
Let y represent the speed of the faster car.
Find the average rate of faster car if one travels 30mph slower than the other. This means that
y = x + 30
They meet after 3.5 hours.
Distance travelled = speed × time
Distance travelled by the slower car is x × 3.5 = 3.5x miles.
Distance travelled by the faster car is y × 3.5 = 3.5y miles. Since the total distance travelled by both cars is 420 miles, therefore,
3.5x + 3.5y = 420
x + y = 120 - - - - - - - - - - -1
Substituting y = x + 30 into equation 1, it becomes
x + x + 30 = 120
2x = 120 - 30 = 90
x = 90/2 = 45
y = x + 30
y = 45 + 30 = 75
