Under Plan A, a 2-minute call costs $0.54 and a 4 minute call cost $1.08. Plan B, the cost for x minutes is given by the equation y= 0.289x. Which plan is cheaper?

Plan A

Step-by-step explanation:

Find the unit rates for each plan

Plan A:

cost/minutes

0.54/2=0.27

1.08/4=0.27

0.27 per minute

Plan B:

The unit rate is given in the equation

The equation is multiplying 0.289 by x (minutes), so each minute must cost  0.289

About 0.29 per minute

Plan A is cheaper because 0.27 is less than 0.289

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6

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;