-9 to the second power will most likely be 81. A negative x a negative equals a positive. Hope this helped.
Answer: 
Step-by-step explanation:
As per given , we have
n = 11
Since population standard deviation is missing, so we use t-test.
Critical t-value for 99% confidence :
[using two-tailed t-value table]
Confidence interval :
Hence, 99% confidence interval for the mean amount of time that students spend in the shower each day.=
i am not shure what the answer is to this?
Well 1/3 for savings means that you save 1/3*4500 or 1500 dollars.
You then have $3000 left. Of this if you spend 50% on food, you spend 0.5*3000 or 1500 dollars on food.
To find the total of 3/4 and 4/5 is to add them together. However, in order to add them together you need to find the least common denominator (LCD). And the LCD of both denominators would be 20, because that is the smallest number both 4 and 5 can divide into. And here is the tricky part, now you have to change the numerators. So since 3/4th's now has a denominator of 20 you have to make the 3 match the 20. So 4 times what it 20? It is 5. So now multiply 5 by three and that will give you 15/20, which can reduce to 3/4 which means that you did this correctly! Now repeat the same steps with 4/5:
4/5=4/20
20÷5=4
4•4=16
16/20 (16/20 can reduce to 4/5 which means you did this correctly.
Now to add them keep the denominators the same and only add the numerators:
15/20 + 16/20 = 31/20
Now this as a mixed number would be 1 11/20. I hope this was helpful!
