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?
Let's solve the question using 1 variable.Anusha.h wrote: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?
Let G = current # of green cars
There are 3 times as many red cars as green cars.
So, 3G = current # of red cars
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NOW WE'll EXAMINE THE INFORMATION FOR TOMORROW
If tomorrow 12 green cars are sold and 3 red cars are added . . .
# of green cars tomorrow = G - 12
# of red cars tomorrow = 3G + 3
. . . then there will be 6 times as many red cars as green cars.
At the moment, we have (G - 12) green cars and (3G + 3) red cars.
These two values aren't equal, because we're told that there are 6 times as many red cars as green cars.
How do we make the 2 values equal so that we can get an equation to work with?
Just multiply the number of green cars by 6.
So, we get 6(G - 12) = 3G + 3
Expand: 6G - 72 = 3G + 3
Rearrange: 3G = 75
Solve: G = 25
Since G = current # of green cars, there are currently 25 green cars.
Cheers,
Brent
