IT means that the students prefer doing homework after school more than before school!
<span>7 / 22 = 31.818181818182%
</span>
HOPE I HELPED!
~Tomas
Answer:
We just add numerators and rewrite denominator.
Adding unlike dominators:
We need to find the same denominators. You need to find the least common multiple (LCM) of the two denominators.
Step-by-step explanation:
You mean unlike denominators and like denominators.
Adding like dominators: We just add numerators and rewrite denominator :
Example : 
Adding unlike dominators:
We need to find the same denominators. You need to find the least common multiple (LCM) of the two denominators.
For example :

LCM for 5 and 4 is 20 : Now, divide by 5 and multiply by 1 for first fraction. 20 divide by 4 and multiply by 3 :

Answer:
A. E(x) = 1/n×n(n+1)/2
B. E(x²) = 1/n
Step-by-step explanation:
The n candidates for a job have been ranked 1,2,3....n. Let x be the rank of a randomly selected candidate. Therefore, the PMF of X is given as
P(x) = {1/n, x = 1,2...n}
Therefore,
Expectation of X
E(x) = summation {xP(×)}
= summation {X×1/n}
= 1/n summation{x}
= 1/n×n(n+1)/2
= n+1/2
Thus, E(x) = 1/n×n(n+1)/2
Value of E(x²)
E(x²) = summation {x²P(×)}
= summation{x²×1/n}
= 1/n