I used a primitive approach (and got the same answer).
We have: .
Since is an integer, is divisible by 13.
The first time this happens is:
2. You have a bag of pink, yellow and green balls.
You have to pick 14 balls to be sure of at least 2 pink.
You have to pick 12 balls to be sure of at least 2 yellow.
You have to pick 8 balls to be sure of at least 2 green.
How many of each color?
I thought of this as: . . . . . so did I!
I just solved the system: .
. . and got: .