This question has been posted here before but the answer was sadly incorrect and I used their approach with different cases and still got it wrong, any help would be appriciated.
I have a bag with 6 marbles numbered from 1 to 6. Mathew has a bag with 12 marbles numbered from 1 to 12. Mathew chooses one marble from his bag and I choose two from mine. In how many ways can we choose the marbles (where the order of my choices does matter) such that the sum of the numbers on my marbles equals the number on his?
Thanks in adavance :D
There are 66 ways... I can come add an explanation here later.
Hope this helps!
Important: " ... where the order of my choices does matter "
If I understand the question correctly, you have only 15 choices:
1 1+2, 1+3, 1+4, 1+5, 1+6
2 2+3, 2+4, 2+5, 2+6
3 3+4, 3+5, 3+6
4 4+5, 4+6
So, the answer is 15