Answer: a) 0.8413, b) 0.9987.
Step-by-step explanation:
Since we have given that
Mean = 3 pounds
Standard deviation = 0.25 pounds
n = 28 bricks
So, (a) What is the probability that all the bricks in the sample exceed 2.75 pounds?

b) What is the probability that the heaviest brick in the sample exceeds 3.75 pounds?

Hence, a) 0.8413, b) 0.9987.
Answer:
missing side length is 12
Step-by-step explanation:
similar means that all correlating pairs of sides have the same ratio (old side length) / (new side length).
so, when we know the ratio of one pair, we can apply it to any other side to calculate the correlating side.
we see, when we go from small to large, that we have the ratio 32/40 = 4/5.
so, multiplying the larger side by this, we get the shorter side.
15 × 4/5 = 3 × 4 = 12
the proportion part in your picture is a bit confusing :
yes,
x/15 = 32/40 = 32/40
I don't know, why this last expression was repeated.
x/15 = 32/40
x = 15×32/40 = 15×4/5 = 3×4 = 12
as you see we get of course the same result doing it that way.
1/4 * 1/3 * 1/2 * 1/1 = 1/24 chance that all 4 letters are placed in the correct envelopes.
With the first envelope, there are 4 choices of letters, so the probability of picking the correct letter is 1/4.
With the second envelope, there are 3 remaining letters, so the probability of picking the correct letter is 1/3.
The same logic follows the the third and final letter.