Carlos bought a $235 water heater with his credit card. he used the water heater for five years before replacing it. he paid off the water heater after two years, making monthly payments. the water heater cost him an average of $1.56 per week in electricity, and $0.78 per week in water. if carlos’s credit card has an apr of 14.15%, compounded monthly, and he made no other purchases with it, what percentage of the lifetime cost of the water heater was interest? (round all dollar values to the nearest cent.)

First we will find the interest on:

P = $235 principal

t = 2 years

r = 0.1415 annual rate

A = future value 

I = A - P the interest

A = P(1 + r)^t

A = 235(1 + 0.1415)^2

A = $306.21

I = A - P

I = $306.21 - $235

I = $71.21

the interest was $71.21.

Next lets find the lifetime cost value:

Lifetime cost value = 306.21 + 5*1.56*52 + 5*0.78*52 = $914.61 (considering that 1 year = 52 weeks)

Now lets find the percentage what percentage the interest is of the lifetime cost:

(71.21/914.61)*100 = 7.79%

the best buy, is the 4- kilogram bag of lollipops for $18.40.

step-by-step explanation:

i found my answer by dividing the cost of each bag by their respective weights.

14.88 divided by 2 = 7.44

17.29 divided by 3 = 5.77

18.4 divided by 4 = 4.6

24.4 divided by 5 = 4.88

by this, i found that the 4 kilo bag is the best buy.

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240