21/j = i + 3/j ; where i is an integer
21/j = ij/j + 3/j
21 = ij + 3
18 = ij
Since j is less than 9, the only options for i are 3, 6, & 9. 3 can be eliminated because it is evenly divided into 21 (therefore no remainder of 3). So the only options for j are 6 and 3.
30/6 = 5 with no remainder 30/3 = 10 with no remainder
Answer: remainder is 0
