Answer:
a) The probability of sampling at random a fish that is smaller in size than the value you would obtain by subtracting half the standard deviation from the average is 0.3085.
b) The probability of sampling at random a fish that is greater in size than the value you would obtain by adding half the standard deviation from the average is 0.3085.
c) The probability of sampling at random a fish that has a size between the two values is 0.383.
d) The 25th and 75 percentiles of fish size for the population using the normal distribution table is 5.69 and 5.87 respectively.
e) The probability that the average calculated will be less than the value is 0.3707.
Step-by-step explanation:
For the given data set mean 
Standard deviation 
Variance 
Here we get is
a)

b)

c)

d)
25th percentile:-
![= 25*[(n+1)/100]th term \\\\= 5.69](https://tex.z-dn.net/?f=%3D%2025%2A%5B%28n%2B1%29%2F100%5Dth%20term%20%5C%5C%5C%5C%3D%205.69)
75the percentile:-
![= 75*[(n+1)/100]th term\\\\ = 5.87](https://tex.z-dn.net/?f=%3D%2075%2A%5B%28n%2B1%29%2F100%5Dth%20term%5C%5C%5C%5C%20%3D%205.87)
e)

I think that the answer is 24 or 32 because of the longitude of that cirlce
Answer:
90 days
Step-by-step explanation:
Let the rate per day for the 30 days period be x
Given that the rate drops to 1/3 of the rate used in 30 days period, it means that the new rate
= 1/3 x
If at a rate of x, the full tank runs for 30 days
at a rate of 1/3 x, the full tank would run for
= x/ (1/3 x) * 30 days
= 3 * 30 days
= 90 days
At the new rate, the full tank of oil will last for 90 days