Gold is 19 times as heavy as water and copper is 9 times as heavy as water. In what ratio should these be mixed to get an alloy 10 times as heavy as water?

• ক 1 : 9 ✅ সঠিক উত্তর
• খ 11 : 9
• গ 13 : 9
• ঘ 1 : 19