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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 15 times as heavy as water ?
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- 1 : 1
- 1 : 2
- 2 : 3
- 3 : 2
Correct Option: D
G = 19W and C = 9W
Let 1 gm of gold is mixed with x gm of copper such that (x + 1) gm of alloy is formed.
∴ 19W + 9Wx = (x + 1) × 15W
⇒ 19 + 9x = 15x + 15
⇒ 15x – 9x = 19 – 15 ⇒ 6x = 4
| ⇒ x = | |
| 3 |
| ∴ Gold : Copper = 1 : | |
| 3 |
= 3 : 2
