Trucks and cars

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Trucks and cars

by cartera » Sun Nov 23, 2008 8:19 am
A certain company that sells only cars and trucks reported that revenues from car sales in 1997 were down 11 percent from 1996 and revenues from truck sales in 1997 were up 7 percent from 1996. If total revenues from car sales and truck sales in 1997 were up 1 percent from 1996, what is the ratio of revenue from car sales in 1996 to revenue from truck sales in 1996 ?

A 1 : 2

B 4 : 5

C 1 : 1

D 3 : 2

E 5 : 3


OA A Can anyone explain how to calculate this question?

I can discard C, D and E but don't know how to differenciate A and B
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by mals24 » Sun Nov 23, 2008 8:39 am
Let the revernue from cars in 1996 = c
revenue from trucks in 1996 = t
Total revenue = c+t

In 1997

revenue from car sales went down by 11%

c - .11c = 0.89c

revenue from truck sales went up by 7%

t+.07t = 1.07t

Total revenue went up by 1%

1.01 (c+t)

0.89c + 1.07t = 1.01 (c+t)
c/t = 0.06/0.12 = 1:2

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by iamcste » Sun Nov 23, 2008 8:44 am

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by dmateer25 » Sun Nov 23, 2008 8:46 am
It's good that you see you can discard C, D, and E.

The easiest and quickest way to solve it once you eliminate these 3 is to just pick some number that satisfy the ratios in the answer choices.


For Answer Choice A:

'96 Car Revenue = 100
'96 Truck Revenue = 200
'96 Total Revenue = 300

'97 Car Revenue = 89 (11% drop)
'97 Truck Revenue = 214 (7% increase)
'97 Total Revenue = 303

303 is a 1 percent increase from 300. Therefore, the ratio is 1:2.


Now if you want to see this algebraically.

Let x = '96 car revenue
let y = '96 truck revenue

.89X + 1.07Y = 1.01(X + Y)
.89X + 1.07Y = 1.01X + 1.01Y
.06Y = .12X
.06/.12 = X/Y
1/2 = X/Y

Ratio of car revenue to truck revenue is 1:2