Which of the following is a result of the construction of a median of a triangle?
1 answer:
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Answer:
Number of cheaper dresses sold is 35
Number of expensive dresses sold is 15
Step-by-step explanation:
Given:
Cost of cheaper dresses = $90
Cost of expensive dresses = $140
Total cost of the dresses = $5250
To Find:
Number of cheaper dress = ?
Number of expensive dress = ?
Solution:
Let
The number of cheaper dresses be x
The number of expensive dresses be y
(Number of cheaper dresses X cost of cheap dress) + (Number of Expensive dresses X cost of expensive dress) = $5250
= $5250
It is given that the 20 more of the cheaper dresses than the expensive dresses is sold
So,
number of cheaper dress = 20 + number of expensive dress
x = 20 + y---------------------------------------(1)
y = 15
Substituting y in (1)
x = 20 +15
x= 35
Answer:
(a)
(b)
Step-by-step explanation:
Let X and Y be discrete random variables and E(X) and Var(X) are the Expected Values and Variance of X respectively.
(a)We want to show that E[X + Y ] = E[X] + E[Y ].
When we have two random variables instead of one, we consider their joint distribution function.
For a function f(X,Y) of discrete variables X and Y, we can define
Since f(X,Y)=X+Y
Let us look at the first of these sums.
Similarly,
Combining these two gives the formula:
Therefore:
(b)We want to show that if X and Y are independent random variables, then:
By definition of Variance, we have that:
Since X and Y are independent, Cov(X,Y)=0
Therefore as required: