Is 2.876 rational or irrational

Concessions at a basketball game cost $1 for a bag of chips and $2.50 for nachos.At the end of the night, 188 items are sold for

Ivenika [448]

Answer: 305 bags of chips were sold

Step-by-step explanation:

6 0

2 years ago

I. In a shipment of 300 connecting rods, the mean tensile strength is found to be 45 kpsi and has a standard deviation of 5 kpsi

CaHeK987 [17]

Answer:

a) Between 39 and 40 rods can be expected to have a strength less than 39.4 kpsi.

b) 260 rods are expected to have a strength between 39.4 and 60 kpsi

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 45, \sigma = 5$

(a) Assuming a normal distribution, how many rods can be expected to have a strength less than 39.4 kpsi?

The percentage of rods with a stength less than 39.4 is the pvalue of Z when X = 39.4. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{39.4 - 45}{5}$

$Z = -1.12$

$Z = -1.12$ has a pvalue of 0.1314

13.14% of rods have a strength less than 39.4 kpsi.

Out of 300

0.1314*300 = 39.42

Between 39 and 40 rods can be expected to have a strength less than 39.4 kpsi.

(b) How many are expected to have a strength between 39.4 and 60 kpsi?

The percentage of rods with a stength in this interval is the pvalue of Z when X = 60 subtracted by the pvalue of Z when X = 39.4. So

X = 60

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{60 - 45}{5}$

$Z = 3$

$Z = 3$ has a pvalue of 0.9987

X = 39.4

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{39.4 - 45}{5}$

$Z = -1.12$

$Z = -1.12$ has a pvalue of 0.1314

0.9987 - 0.1314 = 0.8673

86.73% of the rods are expected to have a strength between 39.4 and 60 kpsi

Out of 300

0.8673*300 = 260

260 rods are expected to have a strength between 39.4 and 60 kpsi

4 0

4 years ago

Brainiliest if u answer both

Lerok [7]

Answer:

1. 48 stickers 2. 1.2 miles

Step-by-step explanation:

1. 12x4=48 stickers. 2. If we let w denote the length of the morning walk, Sierra walks w+2.5w or 3.5w miles each day. At the end of the week she has walked 7 times as far and she said that this was 30 miles. Solving the equation

24.5w=30,

we have w=30/24.5≈1.2 miles. Therefore the distance of Sierra's morning walk is about 1.2 miles

Solution: Using a diagram

We can illustrate the solution to this problem with a tape diagram. If we let one box be the morning walk, then the evening walk is 2.5 boxes. The total distance Sierra walks in one day is represented by 3.5 boxes. Instead of talking about the number of boxes, we can choose a variable to represent the value or length of each box, say w.

Since Sierra walks every day of the week, the total distance walked is 7 times as long. Therefore, we have the total distance walked during the week is 7(3.5w)=24.5w. We know that Sierra walks a total distance of 30 miles, so we have 24.5w=30 miles. We can use another diagram to illustrate the total distance with 24.5 boxes.

Dividing both sides of the equation 24.5w=30 by 24.5 allows us to find w, and we have

w=30/24.5≈1.2.

Therefore, Sierra's morning walk is about 1.2 miles.

4 0

3 years ago

Which expression below does NOT equal 54?

SSSSS [86.1K]

The answer is D
A=54
B=54
C=54
D=48
Merry Christmas

4 0

3 years ago

What is the square root of 121?

salantis [7]

Answer:

11

Step-by-step explanation:

A square root is any number that is multiplies by itself to get a number.

11*11=121

Hope this helps! Plz give brainiest!

4 0

3 years ago

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