Question

4.5g of an alloy of copper and zinc contains 3.5g of copper. what weight of cooper will there be in 18.9g of alloy?

Answer 1

total=4.5g
copper=3.5g in that alloy
zinc=total-copper
      =4.5-3.5
      =1g
so, there is 1g zinc in the alloy
....
now we have to find if there is 18.9g alloy how much copper will be there in that
so, there was 3.5g copper in 4.5g alloy
if we do unitary method then,
let the weight of copper in 18.9g alloy be 'x'
so,
4.5=3.5
18.9=x
18.9*3.5\4.5=x
14.7=x
therefore, there will be 14.7g alloy in 18.9g alloy of zinc and copper
hope this was useful