$39.98 selling price and tax rate 4.5%

Step-by-step explanation:

The marked price is 39.98

The tax is 4.5%

That means that the tax is added on to the marked price to get the selling price.

One way to do is is to multiply by the tax factor.

The tax factor is 1 + 4.5/100 = 1.045

So the Selling price = 39.98 * 1.045

Selling price = 41.78 rounded to 2 decimal places.

The more standard way of doing this is to multiply the tax by the marked price and add that on to the marked price to get the selling price.

39.98 * 4.5/100  = 1.7991

39.98

  1.7991        Add

41.7791

The difference comes in where you do the rounding. The second way to do this has no rounding. If you convert this to money, the answer will be 41.78, just as the first way's answer.

constant of proportionality = 3 and the equation is c = 3p.

step-by-step explanation:

c = kp   where c = amount of caffeine in mg., p = oz of pepsi and k is the constant of proportionality.

substituting the values given:

24 = 8k

k = 3.

the same value of k will be obtained if we substitute the other given values.