An alloy contains 50% iron, 30% zinc, and 20% aluminum. How much iron should be added to 30 kg of the alloy so that the new alloy contains 60% iron?

Solution

ATQ,

Quantity of the alloy = 30 kg

Quantity of iron in 30 kg alloy = (0.50 × 30) = 15 kg

Quantity of zinc in 30 kg alloy = (0.30 × 30) = 9 kg

Quantity of aluminum in 30 kg alloy = (0.20 × 30) = 6 kg

Let the quantity of iron to be added be x kg.

According to the question,

Quantity of iron in the new alloy = (Quantity of zinc + Quantity of aluminum)

(15 + x) = (9 + 6)

Or, x = 15 - 15 = 0

No iron needs to be added as it already satisfies the condition.