They could have assembled total 336 different possible crews.
<em><u>Explanation</u></em>
Total number of trained pilots is 9 and geologists is 4.
The crew should be consisted of 2 pilots and 1 geologist. That means, <u>2 pilots are chosen from total 9 and 1 geologist is chosen from total 4</u>.
Number of ways for choosing 2 pilots from 9 
and
Number of ways for choosing 1 geologist from 4 
So, the total possible number of different crews they could have assembled 
If two events are dependent on each other you have to multiply the probability of the first event times the probability of the second event.
first count all the marbles here there are 21
you are asked about picking two green marbles there are 7 out of the 21 total.
The first event would be 7/21
The second event would be 6/20 (since you didn't replace and you took out a green one)
now multiply your two fractions together:
and you get 1/10.
Substitute 
and 
. Then the integral transforms to
Apply the power rule.
Now put the result back in terms of 
.
U're goal is to get k alone.
So divide both sides by 9/10.
3/2 divided by 9/10 is 5/3
Answer:
1/5
Step-by-step explanation:
this is because 4/20 simplifies to 1/5
give brainliest please.
hope this helps :)
