Help me plz thank u so much.

Mathematics

1 answer:

Vitek1552 [10]3 years ago

6 0

When it say "of" means multiply. So #1 15% of 20 is 15% multiply 20 so 15% will be 0.15 multiply 20 and the answer is 3.

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If the sales tax rate in Alabama is 4 percent and a $20.00 purchase is made.

leonid [27]

Answer:

$20.80

Step-by-step explanation:

20 + 4%(.80) = 20.80

5 0

3 years ago

According to an airline, flights on a certain route are on time 8080% of the time. Suppose 1111 flights are randomly selected

Sergio [31]

Answer:

a. This experiment satisfy the conditions below.

b. 0

c. 0

d. 1

e. 0

Step-by-step explanation:

a. This experiment satisfy the following conditions:

1. The experiment consists of n = 1111 identical trials, i.e., to determine if each flight is on-time or not.

2. Each trial results in success or failure, i.e., the flight is on-time or not.

3. The probability of success in each trial is the same, p = 0.8, because a flight is on-time 80% of the time.

4. The trials are independent because the 1111 flights were selected randomly.

5. Te random variable of interest is Y, the number of on-time flights observed in the n = 1111 flights.

b. P(Y = 99) = $\frac{1111!}{99!(1111-99)!}(0.8)^99(0.2)^{1111-99}$ = 0. This is the probability that 99 flights are on time and 1012 are not.

c. P(Y < 99) = $\sum_{i=1}^{98}\frac{1111!}{y!(1111-y)!}(0.8)^y(0.2)^{1111-y}$ = 0. This is the probability that 0 flights are on-time or 1 flight is on-time or ... or 98 flights are on-time.

d. 1 - P(Y < 99) = 1 - 0 = 1. This is the probability that 99 flights are on-time or 100 flights are on-time or ... or all 1111 flights are on-time.

e. $P(77\leq Y \leq 99) = \sum_{i=77}^{99}\frac{1111!}{y!(1111-y)!}(0.8)^y(0.2)^{1111-y}$ = 0 This is the probability that 77 flights are on-time or 78 flights are on-time or ... or 99 flights are on-time.