Question 35172
Two alloys, alloy A and alloy B, are to be melted down to form another alloy. Alloy B is 19 percent iron. If 42 kg of alloy A and 84 kg of alloy B are melted down and mixed, you will get a new alloy of 31 percent iron. How much iron is contained the alloy A?

Let percentage of iron in alloy A be "x"
Amount of iron in alloy A is 42x
Amount of iron in alloy B s 0.19(84)=16.0 kg
EQUATION:
 iron + iron = 0.31(126)=39.1 kg
42x + 16 = 39.1
42x=23.1
x=0.55= 55%
The percentage of iron in alloy A is 55%
Amount of iron in alloy A = 0.55(42 kg)= 23.1 kg
Cheers,
Stan H.