a) In how many ways can one select two positive integers m,n, not necessarily distinct, so that

Question:

a) In how many ways can one select two positive integers m,n, not necessarily distinct, so that 1 < m < 100, 1 < n < 100 and the last digit of 7m + 3n is 8?
b) Answer part (a) for the case where l < m < 125, 1 < n < 125.
c) If one randomly selects m, n [as in part (a)], what is the probability that 2 is now the last digit of 7m + 3n?