Question
An alloy of artificial gold contains 83% Copper and
remaining Aluminium. In an another alloy, Copper is 91% and Aluminium is 7%. In what ratio should the two alloys be mixed so that the new mixture have 15% Aluminium. Also find the % of Copper in the new mixture?Solution
The alloy should be mix in the ratio of 4:1 Now, 
Difference of 91-83 = 8 8 is divided in the ratio of 4:1 8 × `1/5`  = 1.6% 
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