An alcohol awareness task force at a Big-Ten university sampled 200 students after the midterm to ask them whether they went bar hopping the weekend before the midterm or spent the weekend studying, and whether they did well or poorly on the midterm. The following result was obtained. Did Well on Midterm Did Poorly on MidtermStudying for Exam 80 20Went Bar Hopping 30 70a. What is the probability that a randomly selected student who went bar hopping did well on the midterm?b. What is the probability that a randomly selected student did well on the midterm or went bar hopping the weekend before the midterm?c. What is the probability that a randomly selected student did well on the midterm and also went bar hopping the weekend before the midterm?

(a) The probability that a student who went bar hopping did well on the midterm is 0.30.

(b) The probability that a student did well on the midterm or went bar hopping is 0.90.

(c) The probability that a student did well on the midterm and also went bar hopping is 0.15.

Step-by-step explanation:

The data provided is:

                          Did well (W)   Did Poorly (P)   TOTAL (T)

Studying (S)              80                20                  100

Bar-hopping (B)        30                70                  100

TOTAL (T)                 110                90                 200

(a)

Compute the probability that a randomly selected student who went bar hopping did well on the midterm as follows:

P (W|B) = n (W ∩ B) ÷ n (B)

Thus, the probability that a student who went bar hopping did well on the midterm is 0.30.

(b)

Compute the probability that a randomly selected student did well on the midterm or went bar hopping the weekend before the midterm as follows:

P (W ∪ B) = [n (W) + n (B) - n (W ∩ B)] ÷ N

Thus, the probability that a student did well on the midterm or went bar hopping is 0.90.

(c)

Compute the probability that a randomly selected student did well on the midterm and also went bar hopping the weekend before the midterm as follows:

P (W ∩ B) = n (W ∩ B) ÷ N

Thus, the probability that a student did well on the midterm and also went bar hopping is 0.15.

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.

$25

step-by-step explanation:

25 - 4.50 = 20.5

20.5 / 2 = 10.25

10.25 + 10 = 20.25

20.25 - 12.50 = 7.75

therefore the answer is $25 as shown as the first number.