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A and B are two alloys of gold and copper prepared by mixing metals in ratios 7 : 2 and 7 : 11 respectively. If equal quantities of the alloys are melted to form a third alloy C, the ratio of gold and copper in C will be ;
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- 7 : 5
- 5 : 9
- 9 : 5
- 5 : 7
Correct Option: A
| Gold = | : | = | : | ||||
| 9 | 18 | 18 | 18 |
∴ Gold in new mixture
= 14 + 7 = 21
and copper = 18 × 2 – 21
= 36 – 21 = 15
∴ Required ratio
= 21 : 15 = 7 : 5
