problem: ratio words problems 3
Brass is the alloy of zinc and copper in the ratio 3 : 7
How many kg zinc and copper does 20 kg brass contain?
answer: ratios word problems 3
1. step: given
parts kg
zinc: 3 ?
copper: 7 ?
total amount: 10 20
wanted: kg zinc and copper
2. step: 1 part
1 part = kg total amount : parts total amount
1 part = 20 : 10
1 part = 2 kg
3. step: kg zinc and copper
parts kg
zinc : 3 3 * 2 = 6
copper: 7 7 * 2 = 14
total amount: 10 20
4. step: answer
20 kg brass contains 6 kg zinc and 14 kg copper.