Answer:
0.1274
Step-by-step explanation:
Let X be the random variable that measures the number of children who get their own coat.
Then, the expected value of X is
E[X] = 1P(X=1) + 2P(X=2)+3P(X=3)+...+10P(X=10)
The probability that a child gets her or his coat is
P(X=1) = 1/10
To compute the probability that 2 children get their own coat, we notice that there are 10! possible permutations of coats. The two children can get their coat in only one way, the other 8 coats can be arranged in 8! different positions, so the probability that 2 children get their own coat is
P(X=2) = 8!/10! = 1/(10*9) and
2P(X=2) = 2/(10*9)
Similarly, we can see that the probability that 3 children get their own coat is
P(X=3) = 7!/10! = 1/(10*9*8) and
3P(X=3) = 3/(10*9*8*7)
and the expected value of X would be
E[X] = 1/10 + 2/(10*9) + 3/(10*9*8)+...+10/10! = 0.1274
Answer:
Option (C) is correct .
Step-by-step explanation:
As the expression given in the question as follows.
Now rationalize the expression.
Using the formula
a² - b² = (a - b) (a + b)
Using in the above
As i² = -1
Option (C) is correct .
Answer:
24.27 cm
Step-by-step explanation:
sin 65 degrees = 22/x, so:
1 x
------------------ = ------
sin 65 deg 22
so x = 22 / (sin 65 deg) = 22/0.906 = 24.27 cm
Answer:
x² - 30 + 5x
Step-by-step explanation:
(x + 5)(x − 5)
=x(x − 5)+5(x − 5)
=x² - 5 + 5x - 25
=x² - 30 + 5x
Answer:
16x
Step-by-step explanation:
2x^2(x+3)
2 times 2 = 4
4x(x+3)
4x + 12x =
16x
