In a used car lot, there are 3 times as many red cars as green cars. If tomorrow 12 green cars are sold and 3 red cars

[M7MBA]

In a used car lot, there are 3 times as many red cars as green cars. If tomorrow 12 green cars are sold and 3 red cars are added, then there will be 6 times as many red cars as green cars. How many green cars are currently in the lot?

A. 15
B. 20
C. 25
D. 50
E. 75

[spoiler]OA=C[/spoiler]

Source: Manhattan GMAT

[anonylfc]

Lets assume green cars to be 'x'.
Lets assume red cars to be 'y'

According to first statement => y=3x

Now if 3 red cars are added => y+3
If 12 green cars are sold => x-12
Now the relationship between them ?
=> y+3 = 6 (x-12)

Now we know that y=3x. Hence,
3x+3 = 6(x-12)
3x+3=6x-72
3+72=6x-3x
75=3x
25=x

Which is the answer. Hope this was helpful ! Please upvote if it was !

[Scott@TargetTestPrep]

In a used car lot, there are 3 times as many red cars as green cars. If tomorrow 12 green cars are sold and 3 red cars are added, then there will be 6 times as many red cars as green cars. How many green cars are currently in the lot?

A. 15
B. 20
C. 25
D. 50
E. 75

[spoiler]OA=C[/spoiler]

Solution:

Let r = the number of red cars and g = the number of green cars currently in the lot. We can create the equations:

r = 3g

and

r + 3 = 6(g - 12)

Substituting 3g for r in the second equation, we have:

3g + 3 = 6(g - 12)

3g + 3 = 6g - 72

75 = 3g

25 = g

Answer: C