Ryan is correct, the mean is about 8.1.
To find the mean, you have to add up all the values, then divide by the total amount.
For Sample A:
60 x 6 + 90 x 7 + 145 x 8 + 150 x 9 + 55 x 10 = 4050
If you add up all the adults, you have 500.
Dividing 4050 by 500 = 8.1
Sample B will produce a very similar result.
1. D bc switch the 1/3 into 3/1, then 4 time 3/1 = 12. Basically 4 times 3 =12
2. D
First find the square root of -24 which would be -4.898979486 then either subtract 1 or add negative 1, it's the same thing, and that would give you -5.898979486.
1. - Since a cube is all the same lengths on all sides you would want to find the area of one of the sides. You would do this by multiplying 3.8 by 3.8.
3.8*3.8=14.44
Since you have six faces on a cube you want to multiply this by 6.
14.44*6=86.64
So your answer for 1. is 86.64 in^2 of glass
3. Same thing as number one. Find the face of one side:
1 1/3*1 1/3 is about 1.7777
Multiply this by the six faces.
1.7777*6 is about 10.66666
So your answer for 3. is about 10.666 (repeating) in^2
4. For this one, you want to follow the surface area formula for a cylinder. Which is - A=2πrh+2πr^2
When you put all your numbers in it would look like this:
2*3.14*2*22+2*3.14*2^2
Once you do that equation you will get 301.44
So that should be your answer 301.44 cm^2
Hope this helps!