Answer:
4 stations
Step-by-step explanation:
If we need to be at least 98% certain that an enemy plane flying over will be detected by at least one station, we must ensure that there is at most a 2% chance that no radar stations detect the plane.
The probability that a single radar station does not detect the plane is 0.35.
For n radar stations:

Rounding up to the next whole station, at least 4 stations are needed.
Answer: 0.0170
Step-by-step explanation:
Given : The mean amount purchased by a typical customer at Churchill’s Grocery Store is $23.50, with a standard deviation of $5.00.
i.e. 

We assume the distribution of amounts purchased follows the normal distribution.
Sample size : n=50
Let
be the sample mean.
Formula : 
Then, the probability that the sample mean is at least $25.00 will be :-

Hence, the likelihood the sample mean is at least $25.00= 0.0170
Answer:
4.2 grams in total
Step-by-step explanation:
<h2>
Remember to line up the decimal point when adding numbers that contain decimals.</h2>
3.7
+0.5
_______
4.2