N/13 = 15 with a remainder of 12:
Multiply both sides of this eq'n by 13, to eliminate fractions:
15N = 13(15) + 12 = 195 + 12 = 207
Let's check our answer.
Divide 13 into 207. Using a calculator, we find the quotient is 15.923.
The remainder is 0.923 times 13, or 12.
The number N is 207