Question 978616
x=caramel
2x=peppermint
Those are probabilities.
There are 36 peppermint and 18 caramel (54 total).  3x=54, x=18; 2x=36.

I will now add a pieces of caramel until the fraction of peppermint is now

18+a/54+a will be 2/5, since if the probability of peppermint is 3/5, caramel will be 2/5.
Cross multiply:  2(54+a)=5(18+a)
108+2a=90+5a
18=3a
6=a

add 6 pieces of caramel, and total is 60.
36 are peppermint.
That is 3/5.