Please help.

Find the probability of getting 2 hearts if the cards are drawn from a regular deck and the first card is not replaced.

A true/false quiz consists of twenty questions. If a student answers the twenty questions by making random guesses, what is the probability of getting at least one correct answer?

The first answer is (13/52) x (12/51). That is the probability of two successive draws of hearts.

For the second question, subtract from 1 the probablity of betting none right in 20 attempts. That will leave you with the probabilty of getting at least 1 right.
1 - (1/2)^20 = ?

1 - 1/2 ^20 = 0.999999046

and the first answer is 1/17