Question

Brass is an alloy of Copper and Zinc; Bronze is an alloy containing 80% of Copper, 4% of Zinc and 16% of Tin. A fused mass of Brass and Bronze is found to contain 74% of Copper, 16% of Zinc and 10% of Tin. Find the ratio of Copper to Zinc in the composition of Brass. ( a ) 3 : 2 ( b ) 3 : 5 ( c ) 16: 9 ( d ) Data Insufficient

Answer 1

Let the proportion of Copper and Zinc in Brass be x:y

Also, let the amount of brass and bronze in the fused mass is m and n respectively

Percentage of Tin in the fused mass =m×0+n×16=(m+n)×10⟹10m=6n⟹nm=53

Percentage of Zinc in the fused mass =m×y+n×4=(m+n)×16⟹(y−16)m=12n⟹y−1612=nm=53

⟹3y−48=60⟹y=36

Also, x+y=100⟹x=64

Therefore Ratio of Copper and Zinc in Brass is 64:36