These questions are from an old mock AMC 10 on aops, but I don't know how to solve the questions past #15, and these (below). Here is the link:

https://services.artofproblemsolving.com/download.php?id=YXR0YWNobWVudHMvMS85LzE1ZDRmNWQzOGQyOGZlOTAyZjgzYmNjOGQwM2M4YTgwZjUzMGU2LnBkZg==&rn=TW9ja19BTUNfdmVyczMucGRm

1. Triangle ABC has AB = 3, BC = 4, and AC = 6. Let M denote the

midpoint of BC. The incircle of 4ABC is tangent to AC at N. Segments AM

and BN intersect at O. What is the ratio of the area of quadrilateral MONC

to the area of 4ABC?

2.In a classroom of n students, the teacher forms a committee of two chairmen

at random, and then chooses 1 out of 7 possible elected class presidents. In

another classroom, this time with n − 3 students, the teacher needs to choose

three chairmen, and then choose 1 out of 9 possible class presidents. If the total

number of ways to choose the chairmen and class president for both classes is

the same, then what is the total number of ways for either class? Assume that

chairmen can also be presidents

Guest Jan 20, 2020