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.= 
Answer:
There is one 12/4 in 3.
Step-by-step explanation:
12/4 = 3
4/4 + 4/4 + 4/4 = 12/4 = 3
Answer:
336
Step-by-step explanation:
not completely sure but I'm pretty sure its 336
Answer: c) 2x² - 2x + 4
Step-by-step explanation:
Answer:
- 
Step-by-step explanation:
Step 1: Add the numerator fractions.
2/5 + 3/10
Here we have to find LCD, the LCD of 5 and 10 is 10
(2*2) + 3 4 + 3
Therefore, 2/5 + 3/10 = --------------- = ------------------
10 10
= 7/10
Step 2: Now substitute 2/5 + 3/10 = 7/10 in the given fraction, we get
7/10
= ----------
-7/9
If we have fraction over fraction, we have to find the reciprocal of denominator fraction and multiply.
The reciprocal of -7/9 is -9/7
Step 3: Now multiply 13/10 and -9/7
= (7/10) x (-9/7)
= -9/10
=-9/10
The answer is -