Solve question no. 2 please sir

Dear student,

The total weight of alloy = 50 kg.

weight of lead = $50 * \frac{60}{100} = 30 k g$

let x kg lead must be melted to make alloy contain 75% lead.

therefore

$\frac{30 + x}{50 + x} * 100 = 75 \frac{30 + x}{50 + x} * 4 = 3 4 (30 + x) = 3 * (50 + x) 120 + 4 x = 150 + 3 x 4 x - 3 x = 150 - 120 x = 30 k g$

Thus 30 kg lead must be melted to make the alloy contain 75% lead.

Regards