Question 930971: A private plane takes 8 hours less to travel 960 km than a car. If the plane travels 3 times as fast as the car, what is the speed of the plane and the car?
Found 3 solutions by josgarithmetic, TimothyLamb, MathTherapy:
Answer by josgarithmetic(39617)   (Show Source):
You can put this solution on YOUR website! Travel uniform rates relate quantities of RATE, TIME, and DISTANCE as RT=D.
________________rate_________time________distance
PLANE___________3r___________t-8_________960
CAR_____________r_____________t__________960
The table allows to find the system of equations
 , two equations in two unknown variables.
Answer by TimothyLamb(4379)  (Show Source):
You can put this solution on YOUR website! x = speed of plane
y = speed of car
x = 3y
t = time traveled by car
---
s = d/t
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speed of plane:
x = 960/(t - 8)
3y = 960/(t - 8)
y = 960/3(t - 8)
y = 320/(t - 8)
---
speed of car:
y = 960/t
---
equate speeds:
320/(t - 8) = 960/t
320/(t - 8) - 960/t = 0
320t/t(t - 8) - 960(t - 8)/t(t - 8) = 0
320t - 960(t - 8) = 0*t(t - 8)
320t - 960t + 8*960 = 0
-640t + 7680 = 0
t = 7680/640
t = 12
---
x = 960/(t - 8)
x = 960/(12 - 8)
x = 240
y = 320/(t - 8)
y = 320/(12 - 8)
y = 80
---
answer:
x = speed of plane = 240 kph
y = speed of car = 80 kph
---
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Answer by MathTherapy(10552)  (Show Source):
You can put this solution on YOUR website!
A private plane takes 8 hours less to travel 960 km than a car. If the plane travels 3 times as fast as the car, what is the speed of the plane and the car?
Let speed of car be S
Then speed of plane = 3S
The following TIME EQUATION is thus formed:
2,880 = 960 + 24S ------- Multiplying by LCD, 3S
2,880 – 960 = 24S
1,920 = 24S
S, or speed of car =  , or  km/h
Speed of plane: 3(80), or  km/h
You can do the check!!
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