Question

a bag contains 11 brown, 16 black, 19 gray, and 9 white pebbles. you pick one pebble at random. find the probability that it is black or white. p(black or white) = ?

Explanation:

Step1: Calculate total number of pebbles

$11 + 16+19 + 9=55$

Step2: Calculate number of black or white pebbles

$16 + 9 = 25$

Step3: Calculate the probability

$P(\text{black or white})=\frac{25}{55}=\frac{5}{11}$

Answer:

$\frac{5}{11}$