Brass is an alloy made from copper and zinc in the ratio 3: 2, based on weight. if 120g of copper are needed for a certain piece of brass, how much zinc will be needed for the same piece?

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

i dont know

step-by-step explanation: