All you do is multiply 15 and 6 you get 90. then divide 90 by 9 and you get 10.
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! :)
Answer: 12 boys: 13 Girls
Step-by-step explanation: Nothing much really.
Answer:
x=2
Step-by-step explanation:
i took the quiz
There is no such thing as a "kilowatt per hour". If that's actually what the question says, then it's a defective question, and you should put it away before it makes you any more confused.
A 120 watt light bulb uses exactly 0.12 kilowatt when it's turned on.
In one hour, it uses
(0.12 kilowatt) x (1 hour) = 0.12 kilowatt-hour of energy.
If energy costs $0.20 per kilowatt-hour, then the cost is
(0.12) x (0.20) = 2.4 cents. (0.024 dollar)