Question

There are 8 black balls and 7 red balls in an urn. If 4 balls are drawn without replacement, what is the probability that no more than 1 black ball is drawn? Express your answer as a fraction or a decimal number rounded to four decimal places.

Answer 1

Solution:

Total number of balls = 8 + 7 = 15

Number of red balls = 8

Number of black balls = 7

4 balls are drawn without replacement.

Case (1):

0 black ball is drawn:

This implies that all 4 balls are red.

Hence, total number of ways =

Case (2):

1 black ball is drawn:

This implies that 3 balls are red and 1 balls is black.

Hence, total number of ways =

Total number of ways of drawing 4 balls from a bag of 15 balls =

Hence, probability that no more than 1 black ball is drawn =