Answer:
The first day of spring is Thursday, March 19th.
The first day of summer is June 20th. So, Spring ends on June 20th.
Step-by-step explanation:
<em>I looked it up on the internet instead of asking on brainly.</em>
Answer: 
Step-by-step explanation:
The confidence interval for population mean is given by :-

Given : Sample size : n= 35 , large sample (n>30)
Mean difference : 
Standard deviation : 
Significance level : 
Critical value : 
Now, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students will be :-

Hence, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students = 
Answer:
91 used
65 new
Step-by-step explanation:
7 + 5 = 12
156/12 = 13
7(13) = 91
5(13) = 65
We can simplify it a bit
oh wait,
remember taht x^0=1, no matter what x is
we see the whole thing is to the zero power
the whole thing is equal to 1
doesn't matter what x or y is
the whole thing evaluates to 1