Question

HELP 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?

Answer 1

Answer: 0.81859

Step-by-step explanation:

Using the formula ;

Z = $\frac{x-u}{standard deviation}$

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