25.8%
First, determine how many standard deviations from the norm that 3 tons are. So:
(3 - 2.43) / 0.88 = 0.57/0.88 = 0.647727273
So 3 tons would be 0.647727273 deviations from the norm. Now using a standard normal table, lookup the value 0.65 (the table I'm using has z-values to only 2 decimal places, so I rounded the z-value I got from 0.647727273 to 0.65). The value I got is 0.24215. Now this value is the probability of getting a value between the mean and the z-score. What I want is the probability of getting that z-score and anything higher. So subtract the value from 0.5, so 0.5 - 0.24215 = 0.25785 = 25.785%
So the probability that more than 3 tons will be dumped in a week is 25.8%
the first two are correct, but the answer for c should be 125
Given:
Lamont cotton is 4% commission on the first 10,000 of monthly sales and 10% on all sales over 10,000.
Consider his last month sales is 38,000.
To find:
The total commission.
Solution:
4% commission on the first 10,000 of monthly sales is

Sales over 10,000 is

10% commission on all sales over 10,000 is

Now, the total commission is

Therefore, the total commission is 3,200.