Rafael counted a total of 40 white cars and yellow cars. There were 9 times as many white cars as yellow cars. How many white cars did Rafael count?

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Answer 1 · 2018-05-17T20:56:01

#color(blue)(36)color(white)(8)color(blue)(" white cars"#

Let:

#w="white cars"#

#y="yellow cars"#

9 times as many white cars as yellow:

#w=9y \ \ \ \[1]#

Total number of cars is 40:

#w+y=40 \ \ \ \[2]#

Substituting #[1]# in #[2]#

#9y+y=40#

#10y=40=>y=4#

Substituting this in #[1]#

#w=9(4)=>w=36#

#36\ \ \ \# white cars.

#4 \ \ \ \ \ # yellow cars.