On March 1, 2017, Parnevik Company sold goods to Goosen Inc. for $660,000 in exchange for a five-year, zero-interest-bearing note in the face amount of $1,062,937. The goods have an inventory cost on Parnevik's books of $400,000. Prepare the journal entries for Parnevik on (b) December 31, 2017.

I know the answer is

December 31, 2017

Notes Receivable................................... 55,000

Interest Income

(10% X $660,000 X 10/12)................. 55,000

but i don't understand why there is 10 %

could someone help me please?