Answer: 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
