can't solve

Question

An engineer traveled 165 mi by car and then an additional 675 mi by plane. The rate of the plane was three times the rate of the car. The total trip took 6 h. Find the rate of the car.

Answer 1

165 miles by car, 675 by plane, 3 times as fast by plane 6 hours total time

distance = rate of speed times time traveled

d=rt, p=3c x=time by car =d/c =165/c

165+675 =total distance = distance by car + distance by plane = xc + (6-x)(3c)

840= xc +18c -3xc = 18c -2xc = 18c -2(165/c)(c) = 18c -330

18c = 840+330 = 1170

c = 1170/18 = 65 mph

p = 3(65= 195 mph

or

165/c + 675/3c = 6, multiply by 3c to get

495 + 675 = 18c

18c = 1170

c = 1170/18 = 130/2 = 65 mph = car speed

3c = 195 mph = plane speed

work the problem 2 different ways, odds are high the answer is right, if they're the same

Answer 2

Another way: the total distance was 840. Total time was 6 hours. Average speed of two vehicles was 140.

 

You need an r and a 3r that when added up and divided by the 2 vehicles will give you 140.

 

4r/2=140

4r = 280

R = 70, and 3r = 210

 

 

Answer 3

t = d / r

r represents rate of car

3r represents rate of the plane

165/r + 675/3r = 6

 

Can you solve for r and answer?