1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Galina-37 [17]
3 years ago
5

The completion time for an exam is normally distributed with expected value 75 minutes and variance 12 minutes. What is the prob

ability that a student will finish this exam in less than 70 minutes or more than 80 minutes?
Mathematics
1 answer:
Debora [2.8K]3 years ago
5 0

Answer:

14.89% or 0.1489

Step-by-step explanation:

First, find the z-score for both 70 and 80 minutes and their corresponding percentile.

z= \frac{X - \mu }{SD} \\SD=\sqrt{V} =\sqrt{12}\\\mu =75\\z= \frac{X - 75}{\sqrt{12}}\\\\

For X = 70 minutes:

z= \frac{70 - 75}{\sqrt{12}}\\z=-1.4434

This z-score is equivalent to the 7.445 th percentile, so the probability of a student finishing this exam in less than 70 minutes is 7.445%

or X = 80 minutes:

z= \frac{80 - 75}{\sqrt{12}}\\z=1.4434

This z-score is equivalent to the 92.555 th percentile, so the probability of a student finishing this exam in more than 80 minutes is 100- 92.555 = 7.445%

Therefore, the probability (P) of a student finishing this exam in less than 70 minutes or more than 80 minutes is:

P = 7.445% + 7.445% = 14.89%

You might be interested in
on Saturday Leo and his brother drove into town to visit their mom Leo is trying to remember how much he spent on gas and tolls
Gwar [14]

Let t be the number of tolls they crossed.

Amount they spent at each toll = $1.75.

Amount they spent at gas station = $28.

Let C be the total amount they spent on gas and tolls.

If they crossed 1 toll, then

C = 28 + 1.75(1).

If they crossed 3 tolls, then,

C = 28 + 1.75(3)

If they crossed t tolls, then,

C = 28 + 1.75t

Here, the terms are 28 and 1.75t and the factors are 1.75 and t.

8 0
3 years ago
What solid 3D object is produced by rotating the rectangle about line m?
Roman55 [17]

Answer:

A. A cylinder with diameter 8 units

Step-by-step explanation:

∵ The <u>line</u> m is the <em>central axis</em>

So the radius is 4 units. ∴ Diameter is 8 units.

∵ The picture is a <em>rectangle</em>.

[ The <em>rectangle rotates</em> are its side to form a <em>cylinder</em> ]

So a cylinder with diameter 8 units.

The answer is A.

7 0
1 year ago
Triangle A’B’C is the image ABC under a translation.
grigory [225]
A translation by 3 units to the right.
6 0
3 years ago
How can you tell Is something is a unit rate
ArbitrLikvidat [17]

Unit rate is a ratio between two different units with a denominator of one. When we divide a fraction's numerator by its denominator, the result is a value in decimal form. For example: 8/4 = 2 and 3/6 = 0.5. When we write numbers in decimal form, we can write them as a ratio with one as the denominator.

For example, we can write 2 as 2/1, and 0.5 as 0.5/1. However, since that approach can be a little clumsy, we usually drop the one. That said, it's important to remember the one is there, especially when working with unit rates.

For instance, 8 miles/4 hours = 2 miles/hour. Notice again that, while we did not include the 1, we did include the unit 'hour' Miles per hour is a familiar expression, as are unit rates such as:

interest/amount invested

revolutions/minute

salary/year

Conversationally, the word ''per'' indicates we are using a unit rate.

4 0
3 years ago
Helppp i need help on this question on my hw
yaroslaw [1]

Answer:

B)m^2/3n^5/3

Step-by-step explanation:

 

4 0
3 years ago
Read 2 more answers
Other questions:
  • Solve the mathematical puzzle.
    11·2 answers
  • Can you solve for ×/4+7=5
    8·1 answer
  • Find the volume of the given solid. bounded by the cylinder y2 + z2 = 64 and the planes x = 2y, x = 0, z = 0 in the first octant
    5·1 answer
  • Jeff had $20. He spent 18 of his money on lunch and 25 of his money at the movies.
    15·1 answer
  • Please Help Me?!? File Attached....
    8·1 answer
  • Please help me, as soon as possible!!
    9·1 answer
  • Alex rode his bike 25 kilometers. About how many miles did Alex ride his bike?
    5·1 answer
  • Find the circumference of c round to the nearest hundredth
    15·1 answer
  • For the function f(x) = −2x − 9, identify the values of f(0), f(1/2), and f(−2)
    10·2 answers
  • Angie read 2 books in 5 days, and each book contained 330 pages. If Angie read the same number of pages each day, how many
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!