The ratio of red cars to blue cars in a parking lot was 5:3 . If there was 40 red cars , how many blue cars were there ?

The answer is x equals 24
you set up a proportion new over old
so for red cars 40 over 5
since we don’t know the new for blue cars we’ll use x
so x over 3
we then make them equal to each other
40 x
—- = —-
5 3
cross multiply, then we get
120=5x
isolate the x by dividing 5 from both sides to get 24

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