Copper is 7 times as heavy as water and gold is 13 times as heavy as water. In what ratio should these be mixed to get an alloy 11 times as heavy as water ?	Choose the correct choice from the following
A) 2 : 1 B) 1 : 2 C) 2 : 3 D) 3 : 2 E) 3 : 1
Explanation :   Solution: C = 7W and G = 13W.   Let 1 gm of copper be mixed with x gm of gold to get (1+x)gm of alloy.   (1gm copper)+(xgm gold) = (x+1)gm of alloy.   =&gt;7W+13W*x = (x+1)*11W   =&gt; 7+13x = 11(x+1)   =&gt; 2x = 4 =&gt; x = 2.   .'. Ratio of copper and gold = 1 : 2   Answer : 1 : 2
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Copper is 7 times as heavy as water and gold is 13 times as heavy as water. In what ratio should these be mixed to get an alloy 11 times as heavy as water ?