Answer:
Explanation:
If John needs to ensure a 40% profit, John needs to sell the pines at a price that would give 40% more money back than he spent.
Since John needs to make back all of the money he spent, plus another 40%, John needs to get back 140% of what he spent.

John spent $3500.
140% of $3500 is $4900.
So, John must bring in $4900 (revenue) selling all 15 pines to achieve a 40% profit.
However, the question asks for the price of a single pine. To find the unit price of a single pine, divide the total revenue by 15.

The probability that the the sample mean would be less than x=132.25 will be calculated as follows:
z=(x-σ)/μ
μ- mean
σ- standard deviation
z=(132.25-138)/28=-0.2054
thus:
P(X≤x)=0.4207=42.07%