Answer:
The smallest sample size required to obtain the desired margin of error is 44.
Step-by-step explanation:
I think there was a small typing error, we have that
is the standard deviation of these weighs.
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
So it is z with a pvalue of
, so 
Now, find the margin of error M as such

Which of these is the smallest approximate sample size required to obtain the desired margin of error?
This sample size is n.
n is found when 
So



Simplifying by 15



Rounding up
The smallest sample size required to obtain the desired margin of error is 44.
Answer:
$590
Step-by-step explanation:
The credit card balance on the card is : $215.
You put on his charge 5 chairs that each cost $75.
So 75 * 5 = 375.
You have now added to your credit card balance of $375 and before you bought the chairs, it was $215. You must add these totals to get your new balance after purchasing 5 new chairs for the office.
375 + 215 = 590.