Question

i need help
A store is having a sale on 200 DVD movies. Some of the movies are being sold for $10 and some of them are being sold for $12. If the store made $2200 after selling all 200 DVDs, how many $12 DVDs were sold?
A) 50
B) 75
C) 100
D) 150

Answer 1

@retirEEd

Answer 2

okk have any idea?

Answer 3

if you don't no problem

Answer 4

$10x+$12y= $2200
x+y=200
multiple the bottom equation by -10
So you now
$10x+$12y= $2200
-10x-10y=-2000
(the x's cancel out) nad you are left with 2y=200
y=100 so 100 $12 DVD's were sold

Answer 5

well i had an idea but i didnt finish it because i didnt know how to proceed

Answer 6

\[\text{Solve}[10 (200-x)+12 x=2200,x] \]\[x -> 100 \]

Answer 7

ok