Question

Six hundred people attend the premier of a motion picture. Adult tickets cost $12, and children where admitted for $10. If the box office receipts total $7080, how many children attended the premier?

Answer 1

I am not sure how to set up the formula here.

Answer 2

we know
x+y=600
10x+12y=7080

Answer 3

so you use either elimination or solve for one and use substitutio

Answer 4

do you know how to do either method?

Answer 5

No, I kind of remember substitution place the x, or y in to solve for one but not sure the steps.

Answer 6

ok so I personally feel that elimination would be easier so are you ok if I walk you through that one?

Answer 7

yes

Answer 8

ok so we have
x+y=600 and
10x+12y=7080
so we multiply the top by negative 12 (so we can cancel out the ys
-12x-12y=-7200
10x+12y=7080 so then we add it like adding anything else the ys cancle like we wanted
-2x=-120 solve for x and we get
x=60 so we had sixty children attend

Answer 9

now how do you think we find the number of adults?

Answer 10

same but multiple to top by -10 right?

Answer 11

well you could do that but you already have x right so now you only need y so what could you do that would be easier

Answer 12

plug in the number of children for x

Answer 13

and solve for the y

Answer 14

yes

Answer 15

10*60+12y=7080

Answer 16

so you have to be careful because you have to be careful plugging it back in

Answer 17

the correct answer is 540 that was my bad

Answer 18

because if you plug it into the 10x+12y equation you get the 585

Answer 19

but with x+y you get 540

Answer 20

I just verified it by multiplying by -10 like you thought of before

Answer 21

yeah we know 60 children and 600 attend so could do 600-60

Answer 22

so you just have to verify that's all

Answer 23

good job man

Answer 24

thanks