Answer:
r = 1
Step-by-step explanation:
Use the distributive property to multiply −6 by −3+5r.
18−30r=−5−7r
Add 7r to both sides.
18−30r+7r=−5
Add −30r and 7r to get −23r.
18−23r=−5
Subtract 18 from both sides.
−23r=−5−18
Subtract 18 from −5 to get −23.
−23r=−23
Divide both sides by −23.
r=−23/−23
Divide −23 by −23 to get 1.
r=1
Answer:
<u>603.19</u><u> </u>with pi and <u>602.88</u> with 3.14
Step-by-step explanation:
V = pi times r^2 times h
Answer:
C. (n₁ + n₂ - 2) degrees of freedom
Step-by-step explanation:
The t-test for difference between two mean when variance are equal is:

where ,
= Mean of Sample 1
= Mean of Sample 2
s = standard deviation
n_1 = size of Sample 1
n_2 = size of Sample 2
and t is Student's t-test with (n₁ + n₂ - 2) degrees of freedom.
Answer:
68% of these phones last 3.87 years.
Step-by-step explanation:
Exponential distribution:
The exponential probability distribution, with mean m, is described by the following equation:

In which
is the decay parameter.
The probability that x is lower or equal to a is given by:

Which has the following solution:

The probability of finding a value higher than x is:

The average lifetime of a certain new cell phone is 3.4 years.
This means that 
So

68% of these phones last how long (in years)?
This is x for which:


Then






68% of these phones last 3.87 years.