In january 2003, the american worker spent an average of 77 hours logged on to the internet while at work (CNBC, march 15,2003). Assume the times are normally distribute and that the standard deviation is 20 hours.
a) What is the probability a randomly selected worker spent fewer than 50 hours logged on to the internet?
b) What percentage of workers spent more than 100 hours logged on to hte internet?
c) A person is classified as a heavy user if he/she is in the upper 20% of usage how many hours must a worker have logged on to the internet to be considered a heavy user?

Step-by-step explanation:

Given mean = 77hours, standard deviation = 20hours

a) the probability a randomly selected worker spent fewer than 50 hours logged on to the internet? = P(X < 50)

z = X - mean/SD, where SD = standard deviation

= 50 - 77/20

z = -1.35, P(X < 50) = P(z < -1.35) = 0.0885 from z -table

b) percentage of workers spent more than 100 hours logged on to the internet

= P(X > 100)

z = 100 - 70/20

z = 1.15

P(z> 1.15) = 1 - P(z < 1.15)

= 0.1251, hence percentage of workers spent more than 100 hours logged on to the internet 12.51%

c) from the appendix in the z table

P(z < 0.84) = 1 - 0.20 = 0.80

from x - mean /SD = z

x = mean + zSD

x = 77 + 20 x 0.84

x = 94, how many hours must a worker have logged on to the internet to be considered a heavy user = 94hrs

the final amount you will pay is $68.04.

the tip is determined by the pre-tax amount, so we calculate the tip based on the original bill, not after we've added sales tax.

to find the tip:

we can divide 54.00 by 100 to get 1% of 54. then we multiply that by 18.

54 / 100 = .54

.54 x 18 = 9.72

tip = 9.72$

to find the tax:

we can divide 54.00 by 100 to get 1% of 54. then we can multiply that by 8 to get 8%.

54 / 100 = .54

.54 x 8 = 4.32

tax= 4.32

now we can add the tip and tax to the bill to get our total.

54 + 9.72 + 4.32 = 68.04

total: $68.04

step-by-step explanation:

should have been evaluated with one odd value and one even value. the expressions have equivalent values when . when , the first expression has a value of 3 and the second

step-by-step explanation: