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
Zepler [3.9K]
3 years ago
8

If the 4th and 7th terms of a GP are 250 and 31250 respectively. Find the two possible values of a and r

Mathematics
1 answer:
Over [174]3 years ago
5 0

Answer:

a = 2, r = 5

Step-by-step explanation:

Nth term of a GP = a×r^(n-1)

Where 'a' is the first term and 'r' is the common ratio

4th term = a×r^3 = 250

r^3 = 250/a

7th term = a×r^6 = 31250

a×r^6 = 31250

a×(r^3)^2 = 31250

a×(250/a)^2 = 31250

a×(62500/a^2) = 31250

62500/a = 31250

a = 62500/31250 = 2

a = 2

since r^3 = 250/a,

r^3 = 250/2 = 125

r = (125)^(1/3)

r = 5

You might be interested in
Please help asap !! : (((((
prohojiy [21]

Answer: it is 65%

Step-by-step explanation:

8 0
3 years ago
Two major automobile manufacturers have produced compact cars with engines of the same size. We are interested in determining wh
Molodets [167]

Answer:

(A) The mean for the differences is 2.0.

(B) The test statistic is 1.617.

(C) At 90% confidence the null hypothesis should not be rejected.

Step-by-step explanation:

We are given that a random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance.

The following data (in miles per gallon) show the results of the test;

Driver         Manufacturer A               Manufacturer B

   1                      32                                       28

  2                      27                                       22

  3                      26                                       27

  4                      26                                       24

  5                      25                                       24

  6                      29                                       25

  7                       31                                       28

  8                      25                                       27

Let \mu_1 = mean MPG for the fuel efficiency of Manufacturer A brand

\mu_2 = mean MPG for the fuel efficiency of Manufacturer B brand

SO, Null Hypothesis, H_0 : \mu_1-\mu_2=0  or  \mu_1= \mu_2    {means that there is a not any significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles}

Alternate Hypothesis, H_A : \mu_1-\mu_2\neq 0  or  \mu_1\neq  \mu_2   {means that there is a significant difference in the mean MPG (miles per gallon) for the fuel efficiency of these two brands of automobiles}

The test statistics that will be used here is <u>Two-sample t test statistics</u> as we don't know about the population standard deviations;

                      T.S.  = \frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p\sqrt{\frac{1}{n_1}+\frac{1}{n_2}  } }  ~ t__n__1+_n__2-2

where, \bar X_1 = sample mean MPG for manufacturer A = \frac{\sum X_A}{n_A} = 27.625

\bar X_2 = sample mean MPG for manufacturer B =\frac{\sum X_B}{n_B} = 25.625

s_1 = sample standard deviation for manufacturer A = \sqrt{\frac{\sum (X_A-\bar X_A)^{2} }{n_A-1} } = 2.72

s_2 = sample standard deviation manufacturer B = \sqrt{\frac{\sum (X_B-\bar X_B)^{2} }{n_B-1} } = 2.20

n_1 = sample of cars selected from manufacturer A = 8

n_2 = sample of cars selected from manufacturer B = 8

Also, s_p=\sqrt{\frac{(n_1-1)s_1^{2}+(n_2-1)s_2^{2}  }{n_1+n_2-2} }   =  \sqrt{\frac{(8-1)\times 2.72^{2}+(8-1)\times 2.20^{2}  }{8+8-2} }  = 2.474

(A) The mean for the differences is = 27.625 - 25.625 = 2

(B) <u><em>The test statistics</em></u>  =  \frac{(27.625-25.625)-(0)}{2.474 \times \sqrt{\frac{1}{8}+\frac{1}{8}  } }  ~  t_1_4

                                     =  1.617

(C) Now at 10% significance level, the t table gives critical values between -1.761 and 1.761 at 14 degree of freedom for two-tailed test. Since our test statistics lies within the range of critical values of t, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which <u>we fail to reject our null hypothesis</u>.

Therefore, we conclude that there is a not any significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles.

5 0
3 years ago
Brainliest to who answers correctly
LenKa [72]
The correct answer would be the 3rd one because the number simplified equals that
6 0
3 years ago
Read 2 more answers
Kyle brough a case of 24 12 ounce bottles of water.He drank the same amount of water each day and finished the case after 3 days
Anastaziya [24]

Answer:

96 ounces each day

Step-by-step explanation:

Divide the 24 bottles by 3

24/3 = 8

8bottles per day

8 bottles *12 ounces per bottle

96 ounces each day

3 0
3 years ago
Which statements are true for the given quadrilaterals? Choose all answers that are correct. A. All squares are parallelograms.
Jlenok [28]
B all rectangles are squares
5 0
3 years ago
Other questions:
  • Find the missing coefficient. -___________ y2 − [-5y − y(-7y − 9)] − [-y (15y + 4)] = 0
    5·2 answers
  • Jessica is 4 years younger than Jennifer now. In 10 years, Jessica will be twice the age that Jennifer is now. Find the present
    15·1 answer
  • What do i do i need help
    5·2 answers
  • Posting algebra again :/
    14·1 answer
  • Two brothers bought together 10 books. One brother bought four books. How
    5·2 answers
  • 73 divided by 8 what is the remainer
    10·2 answers
  • For the functions f(x)=5x−3 and g(x)=6x2−3, find (f∘g)(x) and (g∘f)(x)
    11·1 answer
  • In five minutes 25 cars, 8 trucks, 12 vans and 2 motorcycles drove past the house. Which
    15·1 answer
  • PLS DON'T USE LINKS
    9·1 answer
  • Answer correctly for brainliest pleaseeee!!
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!