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%?

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Answer 1 · 2017-02-25T16:39:25

We must add #3# g of thyme

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.