Jason is counting the number of cars that drive by his window. He counted four times as many green cars as red cars, and 6 more red cars than purple cars. If he counted 312 cars total, how many of them were purple?
Jason is counting the number of cars that drive by his window. He counted [NUMBER] times as many green cars as red cars, and [NUMBER] more red cars than purple cars. If he counted [NUMBER] cars total, how many of them were purple?
Let g be the number of green cars, r be the number of red cars, and p be the number of purple cars. We know that g + r + p = 315, r = p + 6, and g = 4r
Substitute the second equation into the third equation to get: g = 4r = 4(p + 6) = 4p + 24
Now substitute the equations that express g and r in terms of p in the equation for the total number of cars: 4p + 24 + p + 6 + p = 315
Now combine like terms to get 6p + 30 = 312
Now subtract 30 from both sides to get 6p = 282
Now divide both sides by 6 to get p = 47
#### 47