How much pure gold (24/24) is to be added to 15.0 grams of 14 K gold (14/24) to obtain 18 K gold (18/24) ?

10 gram gold is added

Explanation:

given data

pure gold = (24/24)

added = 15 grams

gold = 14 K (14/24)

gold = 18 K (18/24)

to find out

How much pure gold added

solution

we know here that when we add gold to get 20 K gold or 22K

so we added here 15 gram 14 K

we consider here m is pure gold added

so by composition here

we get

15 (14K) + m (24 K) = (15 + m) (18) ... 1

solve it and find m

m = 10

so 10 gram gold is added