The awnser is 9.48683298051, hope I helped!
Answer:
66.28% of students study more than 8 hours
Step-by-step explanation:
The percent of students study more than 8 hour can be calculated as
P(X>8)=?
P(X>8)=P((X-mean)/sd>(8-9.92)/4.54)
The calculated z-score is -0.42.
P(X>8)=P(Z>-0.42)
P(X>8)=P(0<Z<-0.42)+P(0<Z<∞)
P(X>8)=0.1628+0.5=0.6628.
Thus, 66.28% of students study more than 8 hours.
9 + x = 17
17 - 9 = x
x = 8
