Asap for brainliest: the time required to finish a test is normally distributed with a mean of 60 minutes and a standard deviation of 10 minutes. what is the probability that a student will finish the test between 40 and 70 minutes?

0.81859

Step-by-step explanation:

Using the formula ;

Z =

where u = mean

Therefore the probability that a student will finish the test between 40 and 70 will be :

P ( 40≤X≤70 ) = P(X≤70) - P(X≤40)

P ( 60-40/10) , P( 60 - 70 / 10)

=  2 , -1

= P (Z ≤ 2) - P( Z ≤ -1 )

From normal table , we have

0.97725 - 0.15866

Therefore the probability that a student will finish the test between 40 and 70 minutes = 0.81859

step-by-step explanation:

when the line is solid:

when the line is dashed:

this > inequality sign means:

this < inequality sign means:

this > inequality sign means:

this < inequality sign means:

about the problem:

srry i'm not done ! i'll

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places