Question

Gunpowder contains 75% of nitre and 10% of sulphur, and the rest of it is charcoal. Find the amount of charcoal in 8 kg of gunpowder.

Answer 1

Total quantity of gunpowder = 8 kg = 8000 g (1 kg = 1000 g)
Quantity of nitre in it = 75% of 8000 g
= $\left(\frac{75}{100}\times 8000\right)$ g = 6000 g = 6 kg

Quantity of sulphur in it = 10% of 8000 g
= $\left(\frac{10}{100}\times 8000\right)$ g = 800 g = 0.8 kg
∴ Quantity of charcoal in it = {8000 − (6000 + 800)} g
= (8000 − 6800) g
= 1200 g = 1.2 kg

Hence, the amount of charcoal in 8 kg of gunpowder is 1.2 kg.