Question

Gabriel is making a mixture of compost and soil to use for a special plant. He wants his final mix to be 2 parts compost to 10 parts potting soil. He wants to end up with 12 kilograms of mix. How many kilograms of compost should Gabriel use?

Answer 1

the answer could be 1/12th.

Answer 2

Since the ratio is 2:10 the total must be a multiple of twelve, and in this case is 12.  So each part is 1/12 of the total or one.

So Gabriel needs to mix 2kg of compost with 10kg of potting soil.