2008 Indonesia MO Problems/Problem 4
Problem
Note: Problem statement slightly modified for correction.
Let .
(a) Find the number of subset of such that the product of its elements is divisible by 7.
(b) Let denotes the number of subset of
in which the sum of its elements, when divided by 7, leaves the remainder
. Prove that
.
Solution
See Also
2008 Indonesia MO (Problems) | ||
Preceded by Problem 3 |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 | Followed by Problem 5 |
All Indonesia MO Problems and Solutions |