A ton of ore is found to contain 20% copper. At that rate, how many tons of ore will be needed to get 10 tons of copper?

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durbanville | High School Teacher | (Level 2) Educator Emeritus

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For every ton of ore there is 20% copper. We therefore need to calculate what will render 10 tons of copper.

Let x = the unknown amount of ore we need.

20% means 20 over 100 and we require an answer of 10

`therefore 20/100 times x = 10`

`therefore x= 10 times 100/20`

`therefore x=50`


The amount of ore required to obtain 10 tons of copper at a rate of 20% per ton of ore is 50 tons.