First calculate the percentage of math.
100-23-30-15-12
=20%
then 150x20% for the math
=30 so there are 30 students chose math.
Answer: 10 is your answer bud ❤
80p=pr^2+p(2r)^2
80p=pr^2+4pr^2
80=r^2+4r^2
80=5r^2
16=r^2
r=4 for the smaller circle´s radius, and 8 is the larger circle´s radius.
Have a nice day, I hope this was helpful :D
Answer:
E(X) = 6
Var(X) = 3.394
Step-by-step explanation:
Let X represent the number of carp caught out of the 20 fishes caught. Now, if we are to assume that each
of the (100, 20) ways to catch the 20 fishes will be equally likely.
Thus, we can say that X fulfills a hypergeometric
distribution with parameters as follows;
n = 20, N = 100, k = 30
Formula for expected mean value in hypergeometric distribution is;
E(X) = nk/N
E(X) = (20 × 30)/100
E(X) = 6
Formula for variance is;
Var(X) = (nk/N) × [((n - 1)(k - 1)/(N-1))) + (1 - nk/N)]
Var(X) = ((20 × 30)/100) × [((20 - 1)(30 - 1)/(100 - 1)) + (1 - (20 × 30/100)]
Var(X) = 6 × 0.5657
Var(X) = 3.394
1.) expand
3x - 15 - 5x = 25 + 6x
2.) simplify
-2x - 15 = 25 + 6x
3.) add 2x to both sides
-15 = 25 + 6x + 2x
4.) simplify
-15 = 25 + 8x
5.) subtract 25 from both sides
-15 - 25 = 8x
6.) simplify -15 - 25 to -40
-40 = 8x
7.) divide both sides by 8
-40/8 = x
8.) x = -5
