Jim’s statement is correct for all numbers greater than or equal to 0. It does not work for negative numbers. For example, the floor of –3.5 is –4, where –4 is not equal to –3, the number before the decimal point. Hope this helps!
Thanks!
-Charlie
Answer:
johanna prepares a mixture of salad mixed with mayonnaise carrots cucumber lettuce and cheese. what type of mixture divine salad is? why do you think so
Answer:
A bag of pop corn costs $8, and each Pretzel costs $4.25.
Step-by-step explanation:
Let 
be the price of popcorn, and 
the price of Pretzels. If the girl bought 2 bags of popcorn and 5 Pretzels and it cost her $37.25, we have the equation
<em>(this says that the cost of 2 popcorn bags plus 5 pretzels equals $37.25)</em> .
And, since Zoe bought 8 popcorn bags and 9 Pretzels with a total price of $102.25, we get the equation
<em> (this says that the cost of 8 popcorn bags plus 9 Pretzels equals $102.25).</em>
Thus, we have two equations
1.
2.
and we solve them by first multiplying equation (1) by 4:
,
and then subtracting it from equation (2):
Now we put this value of into equation (1) and get:
and we solve for to get:
Therefore, a bag of popcorn costs $8, and each Pretzel costs $4.25.
Step-by-step explanation:
percentage
current number/total number * 100
150/400*100 is 37.5%
Answer:
the expected value of Xn , E(Xn) = 0 and the variance σ²(Xn) = n*(1-2n)
Step-by-step explanation:
If X1= number of tails when n fair coins are flipped , then X1 follows a binomial distribution with E(X1) = n*p , p=0,5 and the number of heads obtained is X2=n-X1
therefore
Xn =X1-X2 = X1- (n-X1) = 2X1-n
thus
E(Xn) =∑ (2*X1-n) p(X1) = 2*∑[X1 p(X1)] -n∑p(X1) = 2*E(X1)-n = 2*n*p--n= 2*n*1/2 -n = n-n =0
the variance will be
σ²(Xn) = ∑ [Xn - E(Xn)]² p(Xn) = ∑ [(2X1-n) - 0 ]² p(X1) = ∑ (4*X1²-4*X1*n+n²) p(X1) = = 4*∑ X1²p(X1) - 4n ∑X1 p(X1) - n²∑p(X1) = 2*E(X1²) -4n*E(X1)- n²
since
σ²(X1) = n*p*(1-p) = n*0,5*0,5=n/4
and
σ²(X1) = E(X1²) - [E(X1)]²
n/4 = E(X1²) - (n/2)²
E(X1²) = n(n+1)/4
therefore
σ²(Xn) = 4*E(X1²) -4n*E(X1)- n² = 4*n(n+1)/4 - 4*n*n/2 - n² = n(n+1) - 2n² - n²
= n - 2n² = n(1-2n)
σ²(Xn) = n(1-2n)
