Answer: 
Step-by-step explanation:


The normal distribution curve for the problem is shown below
We need to standardise the value X=405.5 by using the formula


We now need to find the probability of z=0.32 by reading the z-table
Note that z-table would give the reading to the left of z-score, so if your aim is to work out the area to the right of a z-score, then you'd need to do:

from the z-table, the reading

gives 0.6255
hence,

The probability that the mean weight for a sample of 40 trout exceeds 405.5 gram is 0.3475 = 34.75%
Answer: 10%
Step-by-step explanation:
Since the shopkeeper purchased 60 pencil boxes for 4,500, he purchased them at the rate of:
= 4500 / 60
= 85 per pencil box
If the shopkeeper sold them at the rate of 4,125 for 50 pencil boxes, then he sold them at the rate of:
= 4125 / 50
= 82.50 per pencil box.
Therefore the percentage profit will be:
= Gain / Cost price × 100
= (82.50 - 75) / 75 × 100
= 7.5/75 × 100
= 10%
Answer:6.36
Step-by-step explanation:
Multiply the bill($42.40) by 0.15