Question

Brass is made from a mixture of copper and other elements. A mixture that is 80% copper is combined with a mixture that is 60% copper, resulting in 100 pounds of brass that is 65% copper.

Which equation can be used to find x, the amount of 60% mixture used to create the 65% mixture?

a. 0.8(100 – x) + 0.6x = 100(0.65)
b. 0.6(100 – x) + 0.8x = 100(0.65)
c. 0.8(100) + 0.6x = 0.65(100 - x)
d. 0.6(x) + 0.8(100 + x) = 0.65

Answer 1

@mathgeek27

Answer 2

give me a sec :)

Answer 3

I say C, but you should get a second opinion bc I'm not 100% sure @thadyoung what's your opinion?

Answer 4

@cody7744 Is C correct ?

Answer 5

looks right

Answer 6

let 'x' be the amount @ 60%
'y' be the amount @ 80%
0.80y + 0.60x = 100(0.65) ----equation 1
since x and y combined is 100 then
x + y = 100
y = 100 - x ---equation 2
substitute equation 2 to 1
0.80(100 - x) + 0.60x = 100(0.65)

Answer 7

So A ?

Answer 8

yep