Suppose that a single card is selected from a standard 52-card deck. what is the probability that the card drawn is a club? now suppose that a single card is drawn from a standard 52-card deck, but it is told that the card is black. what is the probability that the card drawn is a club?

1. Suppose that a single card is selected from a standard 52-card deck. what is the probability that the card drawn is a club ? 

From the total 52 card, there is 13 club card. There is no scenario that need to be considered in this problem. The probability to draw club would be:
the number of club cards/total number of cards = 13/52= 1/4= 25%

2. suppose that a single card is drawn from a standard 52-card deck, but it is told that the card is black. what is the probability that the card drawn is a club ?

In this scenario, the card is already known as black. Out of 52 cards, there is 26 black card. Out of 26 black cards, there are 13 clubs cards. The probability to draw club would be:

the number of club cards/total number of black cards= 13/26= 1/2= 50%

You are dumb you will drop out of high school