Question

There are 5 red and 4 black balls in a bag. Two draws of two balls
are made from it. Find the probabilities that the first drawing gives
2 red balls and the second drawing gives 2 black balls if (1) the balls
are not replaced (ii) they are replaced.
5 5
Ans. :
63 108
108​

Answer 1

Grit chambers are long narrow tanks that are designed to slow down the flow so that solids such as sand, coffee grounds, and eggshells will settle out of the water. Grit causes excessive wear and tear on pumps and other plant equipment.