Answer:
a) P=0.3174
b) P=0.4232
c) P=0.2594
d) The shape of the hypergeometric, in this case, is like a binomial with mean np=1.
Step-by-step explanation:
The appropiate distribution to model this is the hypergeometric distribution:

a) What is the probability that none of the questions are essay?

b) What is the probability that at least one is essay?

c) What is the probability that two or more are essay?

The left side can be written as a square. We can take the square root, then subtract 1.
... (x +1)² = 17
... x +1 = ±√17
... x = -1 ±√17
45 goes into 240 5.33 times
$1.40 - price from a supplier = 100%
100% + 80% = 180% = 1,8 - the retail price
1,40 * 1,8 = $2,52 - the retail price
100% - 25% = 75% = 0,75 - on sale for 25% off
2,52 * 0,75 = $1,89 - the sale price.