Math

1.

What is $12+7 \bmod 15$?

2.

What are the prime factors of 72?

3.

What is the greatest common divisor of 46 and 210?

4.

Suppose S is the collection of letters in the English alphabet. What is the probability that a letter chosen at random from S is e?

5.

Suppose T is the collection of letters in the word seersucker. What is the probability that a letter chosen at random from T is e?