Answer:
4.
Step-by-step explanation:
2 to the second power = 2^2.
2^2 means 2*2 = 4.
The 2 in ^2 is called the 'exponent' .
Note 3^3 = 3*3*3
and 5^5 = 5*5*5*5*5.
Let W = number of white cars, and Y = number of yellow cars.
There were 9 times as many white cars as yellow cars. This means that the number of white cars was 9 times more than the number of yellow cars. This can be translated by the expression:
9Y = W
The person counted 40 cars in total:
W + Y = 40
So we get the system:

In the first equation, we multiply by 9:
9W + 9Y = 360
In the second equation:
9Y= W
W-9Y = 0
Then we add the first with the second equation:
9W + 9Y + W - 9Y = 360
10 W = 360
W = 36
So He counted 36 white cars.
Hope this Helps! :)
Have you tried asking a teacher for help before this
and did you try to take notes cuse notes are your best friends