Gabriel is making a mixture of compost and soil to use for a special plan he wants his final mix to be two part compost to 10 parts potting soil he wants to end up with tim kilograms of mix how many kilograms of compost should gabriel use

Ten is mistakenly written by Tim in question.
Gabriel is making a mixture of compost and soil. In which he wants to mix 2 part compost to 10 parts potting soil. And he wants to end up with ten kilogram
It means compost is 2 pars out of 12 and potting soil is 10 parts out of 12
so, (2 / 12) x 10 kilogram of compost is used
= 1.66667 kilogram of compost Gabriel should use.

She should use 12/3 to measure