Answer:
(a) 0.2721
(b) 0.7279
(c) 0.2415
Step-by-step explanation:
(a) If we choose only one student, the probability of being a math major is 
(because there are 5 math majors in a class of 18 students). So, the probability of not being a math major is 
(we subtract the math majors of the total of students).
But there are 4 students in the group and we need them all to be not math majors. The probability for each one of not being a math major is 
and we have to multiply them because it happens all at the same time.
P (no math majors in the group) = 
= 0.2721
(b) If the group has at least one math major, it has one, two, three or four. That's the complement (exactly the opposite) of having no math majors in the group. That means 1 = P (at least one math major) + P (no math major). We calculated this last probability in (a).
So, P (at least one math major) = 1 - P(no math major) = 1 - 0.2721 = 0.7279
(c) In the group of 4, we need exactly 2 math majors and 2 not math majors. As we saw in (a), the probability of having a math major in the group is 5/18 and having a not math major is . We need two of both, that's 
. But we also need to multiply this by the combinations of getting 2 of 4, that is given by the binomial coefficient 
.
So, P (exactly 2 math majors) = 
= 
= 0.2415
Your first step should be to plug in the q and f values they give you. q being 20 and f being 16. From there you want to isolate 1/p by subtracting the 1/20 from both sides. You should be left with 1/p = 1/16 - 1/20. This will come out to be 1/80 or 0.0125. Now that one side is 1/p and the other is 1/80 you can multiply both sides by p in order to get 1=1/80 times p which means that p = 80 . Hope this helps
Answer:
$52.11
Step-by-step explanation:
23.16÷4=5.79
5.78×9=52.11
Step-by-step explanation:
4(x-3) -r+2x =5(3x-7) - 9x
4x−12r+2x=15x−35−9
6x - 12 = r - 12 = r + 6x -35 -12
r=35-12
r =23
Answer:
There are 41 chickens and 9 cows
Step-by-step explanation:
9(4) = 36
41(2) = 82
82 + 36 = 118
