Answer:
74.72
Step-by-step explanation:
Given
mean
Standard deviation 
For Top 25%

and Z value for 75 % is 0.6744
Thus score which separates the Top 25% of students is


Answer:
x ≈ 8.66
Step-by-step explanation:
Using the sine ratio in the right triangle
sin60° =
= 
Multiply both sides by 10
10 × sin60° = x, thus
x ≈ 8.66 ( to 2 dec. places )
X - 1 < = 9 or 2x > = 24
x < = 9 + 1 x > = 24/2
x < = 10 x > = 12
closed circle on 10, shaded to the left
closed circle on 12, shaded to the right
________10_______12__________
<====X X======>
the X represents closed circles