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
slava [35]
3 years ago
12

Karen can paint a wall in 2.5 hours. Stephanie takes 1.25 hours to paint the same size wall. How many minutes will it take for K

aren and Stephanie working together to paint the same wall?
Mathematics
1 answer:
lorasvet [3.4K]3 years ago
8 0
If Karen takes 2.5 hours to paint the whole wall, then in an hour she paints a fraction of 2/5.
On the other hand, if Stephanie takes 1.25 hours then in an hour she paints a fraction of 4/5 of the wall.
When the two are working together then one hour they will paint a fraction of  6/5 of the wall. But the wall is one whole therefore it will take 5/6 hours or 50 minutes for them to paint the whole wall together. The answer is 50 minutes
You might be interested in
Whats the capacity of a water bottle thats 8 inches
suter [353]
1 pt; or 1 pint seems most reasonable here.

8 0
3 years ago
The International Air Transport Association surveys business travelers to develop quality ratings for transatlantic gateway airp
motikmotik

Answer:

The 95% confidence interval for the population mean rating is (5.73, 6.95).

Step-by-step explanation:

We start by calculating the mean and standard deviation of the sample:

M=\dfrac{1}{n}\sum_{i=1}^n\,x_i\\\\\\M=\dfrac{1}{50}(6+4+6+. . .+6)\\\\\\M=\dfrac{317}{50}\\\\\\M=6.34\\\\\\s=\sqrt{\dfrac{1}{n-1}\sum_{i=1}^n\,(x_i-M)^2}\\\\\\s=\sqrt{\dfrac{1}{49}((6-6.34)^2+(4-6.34)^2+(6-6.34)^2+. . . +(6-6.34)^2)}\\\\\\s=\sqrt{\dfrac{229.22}{49}}\\\\\\s=\sqrt{4.68}=2.16\\\\\\

We have to calculate a 95% confidence interval for the mean.

The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.

The sample mean is M=6.34.

The sample size is N=50.

When σ is not known, s divided by the square root of N is used as an estimate of σM:

s_M=\dfrac{s}{\sqrt{N}}=\dfrac{2.16}{\sqrt{50}}=\dfrac{2.16}{7.071}=0.305

The degrees of freedom for this sample size are:

df=n-1=50-1=49

The t-value for a 95% confidence interval and 49 degrees of freedom is t=2.01.

The margin of error (MOE) can be calculated as:

MOE=t\cdot s_M=2.01 \cdot 0.305=0.61

Then, the lower and upper bounds of the confidence interval are:

LL=M-t \cdot s_M = 6.34-0.61=5.73\\\\UL=M+t \cdot s_M = 6.34+0.61=6.95

The 95% confidence interval for the mean is (5.73, 6.95).

4 0
3 years ago
Find the value of x and the value of y
Doss [256]

Answer:

C

Step-by-step explanation:

These sides are in a ratio:

1 : 2 : \sqrt{x} 3

Therefore:

6 0
2 years ago
A true/false test has 40 questions. Suppose a passing grade is 30 or more correct answers. Test the claim that a student knows m
Angelina_Jolie [31]

Answer:

z≈3.16

p≈0.001

we reject the null hypothesis and conclude that the student knows more than half of the answers and is not just guessing in 0.05 significance level.

Step-by-step explanation:

As a result of step 2, we can assume normal distribution for the null hypothesis

<em>step 3:</em>

z statistic is computed as follows:

z=\frac{X-M}{\frac{\sqrt{p*(1-p)} }{\sqrt{N} } } where

  • X is the proportion of correct answers in the test (\frac{30}{40})
  • M is the expected proportion of correct answers according to the null hypothesis (0.5)
  • p is the probability of correct answer (0.5)
  • N is the total number of questions in the test (40)

z=\frac{0.75-0.50}{\frac{\sqrt{0.5*(0.5)} }{\sqrt{40} } } ≈ 3.16

And corresponding p value for the z-statistic is p≈0.001.

Since p<0.05, we reject the null hypothesis and conclude that the student knows more than half of the answers and is not just guessing in 0.05 significance level.

7 0
3 years ago
Need help on this please help
kobusy [5.1K]

Answer:

The measure of ∠A is 127°.

Step-by-step explanation:

The interior angles of a triangle always add up to 180°. Since you can fix <em>three</em> triangles into a pentagon, the sum of its interior of angles is 540° You could also look at how many angles there are (5), multiply that number by 180°, then subtract 360° from the product.

540° - (113° + 80° + 130° + 90°) = ∠A

540° - 413° = 127°

∠A = 127°

<em>Hope this helps,</em>

<em>~ Nicki ~</em>

8 0
3 years ago
Read 2 more answers
Other questions:
  • Anyone Know This Answer ASAP ?
    7·1 answer
  • A six-sided die (with numbers 1 through 6) and an eight-sided die (with numbers 1 through 8) are rolled. What is the probability
    12·1 answer
  • Scientists study ways to increase the population of wild salmon. How many salmon eggs may be needed to produce 18 adult salmon?
    12·1 answer
  • 5x + 6 = 4x - 2<br>What is x?​
    7·2 answers
  • There are 3 white marbles and 7 blue marbles in a bag.Jamie will randomly pick two marbles out of the bag without replacing the
    8·2 answers
  • The Diplodocus dinosaur is believed to have become extinct approximately 1.38 x 108 years ago.
    10·1 answer
  • Can someone help me
    15·1 answer
  • Please help a girl out!! really confused
    10·1 answer
  • Answered
    5·1 answer
  • Just giving out points for no reason lol
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!