A chemical company makes two brands of antifreeze. The first brand is 55% pure antifreeze, and the second brand is 80% pure antifreeze. In order to obtain 180 gallons of a mixture that contains 65% pure antifreeze, how many gallons of each brand of antifreeze must be used?

Step-by-step explanation:

the first brand = (65-55)/(80-55) x 180

= 10/25 × 180

= 72 gallons

the second brand = (80-65)/(80-55)×180

= 15/25 × 180

= 108 gallons

john earns $14.00 for two hours of work.

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;