Answer:
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:
Answer:
100
Step-by-step explanation: its the same thing but in a different form
Given that the subway stations are 930 m apart, the train have to be accerelated for half the distance and then decerelated for the rest of the distance.
Recall that the distance travelled by an object with an initial velocity, u, for a period of time, t, at an accereration, a, is given by
But, we assume that the train accelerates from rest, thus
The maximum speed is attained at half the center of the distance between subway stations (i.e. at distance = 465 m).
Thus, maximum speed = distance / time = 465 / 23.12 = 20.11 m/s.
