Question

A spice mixture is 25% thyme. How many grams of thyme must be added to 12 g of the mixture to increase the thyme content to 40%?

Answer 1

We must add `3` g of thyme

Explanation:

As spice mixture is `25%` thyme, in `12` g of the mixture

we have `12xx25/100=3` g of thyme.

If we add `x` g of thyme,

we have `x+3` g of thyme and `12+x` g of mixture

but this should be `40%=40/100`

Hence `(x+3)/(12+x)=40/100`

i.e. `100x+300=480+40x`

or `100x-40x=480-300`

or `60x=180`

i.e. `x=180/60=3`

Hence, we must add `3` g of thyme

then we have `6` g of thyme in `15` g of mixture.