Two alloys, of which the first contains 20% nickel and the second contains 40% nickel, were fused with each other

Two alloys, of which the first contains 20% nickel and the second contains 40% nickel, were fused with each other, obtaining 180 kg of an alloy containing 25% nickel. How many kilograms was the mass of the first alloy?

Let’s denote the weight of the first alloy through x, then it contains (x * 0.2) kg of nickel (20%)

The weight of the second alloy will be (180 – x), and the nickel in it (180 – x) * 0.4 = 72 – 0.4 * x.

The mass of nickel in an alloy of two pieces is 180 * 0.25 = 45 kg.

Let’s make the equation:

0.2 * x +72 – 0.4 * x = 45;

0.2 * x = 27;

x = 135 kg.

Answer: The mass of the first ingot is 135 kg.