12 yellow balls and 9 red balls are placed in an urn. two balls are then drawn in succession without replacement. what is the probability that the first ball drawn is a red ball if the second ball drawn is yellow?

Step-by-step explanation:

When the first draw is done there are 9 red balls in a sample size of 21. So there probability of drawing a red ball will be

When the second draw is done, there will be 12 yellow balls in a sample size of 20 since the first ball will not have been replaced into the bag. So the chance of someone drawing the second ball in the second draw is

The probability of them happening in this order is the product of both probabilities:

d) 48

step-by-step explanation:

16,32,48,64,80,96,112,128,144,160,176,192,208,224,240,256,272,288,304,320,336