The three-digit positive integer has a ones digit of 3. What is the probability that is divisible by 13? Express your answer as a common fraction.
Between 100 and 999, there are:999 - 100 + 1 =900 three-digit integers.
900 / 13 = 69 of them are multiples of 13
143 273 403 533 663 793 923 Total = 7 of those 69 are multiples of 13 and end in 3.
Probability is = 7 / 900 - that it is multiple of 13 and ends in 3
