Answer: she scored 69 points on the second test.
Step-by-step explanation:
Let x represent the number of points that she scored in the first test.
Let y represent the number of points that she scored in the second test.
If her mean score was 75, it means that
(x + y)/2 = 75
x + y = 75 × 2
x + y = 150- - - - - - - - - 1
If she scored 12 points more on the first test than the second test, it means that
x = y + 12
Substituting x = y + 12 into equation 1, it becomes
y + 12 + y = 150
2y + 12 = 150
2y = 150 - 12
2y = 138
y = 138/2
y = 69
Answer:
4
Step-by-step explanation:
Answer:
Height is 8cm
Step-by-step explanation:
A= bxh
9.6 = 1.2 x h
÷1.2
8 = h
Check:
8 x 1.2= 9.6cm
Hope this helps!
<span>The area of the base is x^2> The height is h. Each side of the box has area xh. There are 4 sides of the box so the total surface area of the box is x^2+4xh and that is equal to 1000. Solve that equation for h:
x^2+4xh = 1000 h = (1000-x^2)/4x so the Volume = x^2[(1000-x^2)/4x]
Simplify and get V = 250x-x^3/4
The volume will be a maximum when its first derivative is 0.
V' = 250-3/4x^2
Set to 0 and solve. x=18.26
Now plug into the volume function to find the maximum volume:
V=250(18.26)-(18.26)^3/4
V= 4564.35 - 1522.10 =3042.25</span>
