Answer: C) 4.20
Explanation:
Multiply each value with its corresponding frequency:
- 1*450 = 450
- 10*35 = 350
- 50*10 = 500
- 100*4 = 400
- 400*1 = 400
Add up the products
450+350+500+400+400 = 2100
Then divide this over the total frequency (450+35+10+4+1 = 500)
So we get 2100/500 = 4.20 as the expected value.
cylinder:
V = πr²h
V = 3.14(2)² * 3
V = 3.14(4) * 3
V = 3.14(12)
V = 37.7m³
rectangular prism:
V = lwh
V = (2.4)(9)(5)
V = 108m³
the entirety of the sculpture:
V = volume of cylinder + volume of rectangular prism
V = 37.7 + 108
<u>V = 145.7m³</u>
The system is:
i) <span>2x – 3y – 2z = 4
ii) </span><span>x + 3y + 2z = –7
</span>iii) <span>–4x – 4y – 2z = 10
the last equation can be simplified, by dividing by -2,
thus we have:
</span>i) 2x – 3y – 2z = 4
ii) x + 3y + 2z = –7
iii) 2x +2y +z = -5
The procedure to solve the system is as follows:
first use any pairs of 2 equations (for example i and ii, i and iii) and equalize them by using one of the variables:
i) 2x – 3y – 2z = 4
iii) 2x +2y +z = -5
2x can be written as 3y+2z+4 from the first equation, and -2y-z-5 from the third equation.
Equalize:
3y+2z+4=-2y-z-5, group common terms:
5y+3z=-9
similarly, using i and ii, eliminate x:
i) 2x – 3y – 2z = 4
ii) x + 3y + 2z = –7
multiply the second equation by 2:
i) 2x – 3y – 2z = 4
ii) 2x + 6y + 4z = –14
thus 2x=3y+2z+4 from i and 2x=-6y-4z-14 from ii:
3y+2z+4=-6y-4z-14
9y+6z=-18
So we get 2 equations with variables y and z:
a) 5y+3z=-9
b) 9y+6z=-18
now the aim of the method is clear: We eliminate one of the variables, creating a system of 2 linear equations with 2 variables, which we can solve by any of the standard methods.
Let's use elimination method, multiply the equation a by -2:
a) -10y-6z=18
b) 9y+6z=-18
------------------------ add the equations:
-10y+9y-6z+6z=18-18
-y=0
y=0,
thus :
9y+6z=-18
0+6z=-18
z=-3
Finally to find x, use any of the equations i, ii or iii:
<span>2x – 3y – 2z = 4
</span>
<span>2x – 3*0 – 2(-3) = 4
2x+6=4
2x=-2
x=-1
Solution: (x, y, z) = (-1, 0, -3 )
Remark: it is always a good attitude to check the answer, because often calculations mistakes can be made:
check by substituting x=-1, y=0, z=-3 in each of the 3 equations and see that for these numbers the equalities hold.</span>
Answer:
$7075 or 7718
Step-by-step explanation:
91100-6200=84900
84900/11= 7718.18181818 or rounded= 7718
(This is if the december month doesnt count.)
84900/12=7075
(If december is included.)
