Question

An ore contains 12% of copper. How many kilograms of the ore are required to get 69kg of copper?

Answer 1

Let, the amount of ore be X kg.
According to the question

12% of X Kg =69 kg
12/100×Xkg=69 kg
3/25X kg=69 kg
X Kg =(69 Kg ÷3/25)
=(69 Kg ×25/3)
=575 kg
Hence, the amount of ore is required =575 kg

Answer 2

$\huge \tt \color{pink}{Method:}$

Let the amount of ore be X kg.

According to question

12% of X kg= 69kg

12/100× Xkg= 69kg

3/25 Xkg= 69kg

X kg= (69Kg \div3/25)

= (69kg×25/3)

= 575kg

Hence, the amount of ore is 575kg