Question

An ore contains 20 percent zinc. How many kg of ore will be required to get 45kg of zinc.

Answer 1

given that an ore contains 20% zinc

let number of kg of ore required to get 45 kg zinc = x

20% of x = 45kg

⇒ 20/100 × x = 45kg

⇒ x/5 = 45kg

⇒ x = 5 × 45 = 225kg

hence 225 kg of ore will be required to get 45 kg zinc