A store used to sell an MP3 for $72which is 50% more than the wholesale cost. At a special holiday sale, the price of the MP3 was 20% less than the wholesale cost. What was the special sale price of the MP3?

$115.2

Step-by-step explanation:

Step one:

Given data

A store used to sell an MP3 for $72 and we are told that this 50% of the wholesale price.

Therefore the wholesale price is

72*2= $144

Required:

The special sales cost at 20% discount

Step two:

We are told that the special sale is at a 20% discount on the wholesale

= 20/100*144

=0.2*144

=$28.8

Therefore the special sales price is

= 144-28.8

=$115.2

d. 24+-0.114

step-by-step explanation:

the question requires us to calculate the approximate 95% confidence interval for the mean number of ounces of ketchup per bottle in the sample given the following statistics;

sample mean = 24

standard deviation, σ = 0.4

sample size , n = 49

the confidence interval for a population mean is calculated using the formula;

sample mean ± z-score*(σ/sqrt(n))

the z-score associated with a 95% confidence interval, from the standard normal tables, is;

1.96

substituting these values into the formula;

24 ± 1.96*(0.4/7)

= 24 ± 0.112

from the alternatives given, choice d is closest to the above expression;