2:50
1:14
0:14
--------
4:18 hours
They came back at 2:45
So, the movie started at 11:27 AM
Answer:
And rounded up we have that n=421
Step-by-step explanation:
We know that the sample proportion have the following distribution:
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by 
and 
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that 
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
We assume that a prior estimation for p would be 
since we don't have any other info provided. And replacing into equation (b) the values from part a we got:
And rounded up we have that n=421
Answers: 1:B, 2:450
How-To:
Using the formula for area on the bottom of the can, (pi*r^2) you can then multiply by the amount of height missing, which is 4.
Since it was originally 10, you subtract 4 in order to get 6.
That's how to get 4.
Now, plug in pi*r^2 into a calculator (or if you must work it out, radius, r, is 10, so 10*10 is 100. 100*3.14159265 is 314.159265
Now multiply 314 by the height missing (4) to get approximately 1257.
Now for number 2.
It says it is dilated by a scale factor of 1:3 (from 1350). That means that it was made smaller, (that's what dilated means) by 3 for every 1. So take 1350 and divide it by 3 to get 450
