## ksf-2015-ec-20

Peter has ten balls, numbered from 0 to 9.

He distributed these balls among three friends:

John got three balls, George four and Ann three.

Then he asked each of his friends to multiply the numbers on the balls they got, and the results were:

0 for John, 72 for George and 90 for Ann.

Question:

What is the sum of the numbers on the balls that John received?