Avendor buys milk at a certain price, adds water and sells the adulterated milk at the same rate as he bought it for. he makes a 30% profit. what is the percentage of water that he adds to milk?

options:
a) 30%
b) 15%
c) 20%
d) 60%

The correct option is A): "30%" because suppose vendor bought 100 ltr milk at 10/ltr so cost price =1000 rs.
In that he adds "x" ltr of water in order to get profit of 30% above cost price , means his total earnings from adulturated solution will be 1300 rs.

Then why is the question on here if you know the answer

Ithink the answer is b