Daniel's divisible sums
Number Theory
Level
4
Consider the sets \[\begin{align} A &= \{15, 22, 31, 45, 56, 67, 79 \} \\ B &= \{2, 3, 5, 6, 7, 9,12, 24 \} \\ C &= \{14, 21, 31, 40, 53, 62, 78, 81, 90 \} \\ D &= \{11,12, 17,23,54,55,62,98,110,111 \}. \end{align}\]
How many ways are there to choose a number out of each set such that the sum of the four numbers is a multiple of \(8\)?
This problem is posed by Daniel W.
by
Mei Li