Two alloys were combined with a copper content of 40% and 60% to give an alloy containing 45% copper
Two alloys were combined with a copper content of 40% and 60% to give an alloy containing 45% copper. Find the ratio of the mass of the 40% copper alloy to the mass of the 60% copper alloy.
Let’s introduce variables:
p is the mass of the first alloy;
v is the mass of the second alloy.
The first alloy contains forty percent copper. The mass of the alloy is p kilograms. Let’s find the mass of copper in the first alloy.
p * 40% = 0.4p (kg)
The second alloy contains sixty percent copper. The mass of the alloy is v kilograms. Let’s find the mass of copper in the second alloy.
v * 60% = 0.6v (kg)
The total mass of copper in both alloys is 0.4p + 0.6v kilograms.
The two alloys are combined. The mass of the resulting alloy is p + v kilograms.
According to the condition of the problem, the resulting alloy contains forty-five percent copper. Let’s find out how many kilograms of copper are in the resulting alloy.
0.45 * (p + v) = 0.45p + 0.45v (kg)
So, in the resulting alloy, 0.45p + 0.45v kilograms of copper.
And we previously found out that the total mass of copper in the two alloys is 0.4p + 0.6v kilograms. This means that the resulting alloy contains 0.4p + 0.6v kilograms of copper. We can make an equation.
0.45p + 0.45v = 0.4p + 0.6v.
Move 0.4p from the right side of the equation to the left side of the equation.
0.45p + 0.45v – 0.4p = 0.6v;
0.05p + 0.45v = 0.6v.
Move 0.45v from the left side of the equation to the right side of the equation.
0.05p = 0.6v – 0.45v;
0.05p = 0.15v.
p = 0.15v / 0.05;
p = 3v.
Divide both sides of the equation by v. We can do this because we know that v ≠ 0.
p / v = 3.
We found that the mass of the first alloy is related to the mass of the second alloy as three to one.
The answer is three to one.