Answer:70.434
Step-by-step explanation:
A: Suppose Mr. Moore decides to use 20 seventh graders as the sample. Is this sample a random sample? Explain your reasoning.
Ans: No, because he only chose the seventh graders which is invalid since he wants to have to use the mean height which involves the 6th, 7th and 8th graders.
B: Mr. Moore decides to use a random number generator to select 20 students from the school. Suppose that when choosing 20 students using the random generator on the graphing calculator, Mr. Moore’s sample is all eighth graders. Does that mean the sample is not a random sample? Explain your reasoning.
Ans: No, it is still a random sample. Since he is using a random generator, there is a possibility that the random generator would pick all students from the 8th grade. Unlike the first one, the random generator is not biased towards any grade, it is just a coincidence.
It would be either C or A, sorry I cant help anymore than that
If you have 8 yellow balloons for every 12 blue balloons, then if you have 20 balloons in total, 8 out of 20 of those balloons will be yellow. Then you can set up this ratio:

Then, you can use either cross multiplication or multiply the numerator and denominator by the same number to help solve for x. Personally, I prefer cross multiplication, so that's what I'll show you here:

Finally, solve for x:

If you had 100 balloons, you will have
40 yellow balloons.
Hope this helps!!
In order to write this in scientific notation, we must move the decimal from the beginning all the way to between the 5 and the 9
Note: you can move the decimal anywhere you want but typically scientific notation will have the decimal in between the first and second digit.
Since we move the decimal 24 digits to the right, our answer will be
5.972 * 10^24
or
5.972E24
Hope this helps!!