math-algebra?

[Zeenat S]

1. A teacher has a set of 12 problems to use on a math exam. The teacher makes different versions of the exam by putting 10 questions on each exam. how many different exams can the teacher make?

A.12!
11!
B. 66
C.132
D.12!

2. Car thieves steal one autmobile out of 400 of a certain type every year in a certain city. what annual new premium should an owner pay for theft insurance in the amount of $16,000 on a certain type of car?

A. $4
B. $16
C. $40
D. $400

[Megan J]

1) you have to use the combination formula. how many ways to choose 10 questions from 12 questions. your calculator has an nCr button you can use or the formula:
nCr = (n!) / [r!(n-r)!]

12 C 10 = 66

2) I don't know how to do this one sorry