1. Joe buys a cell phone marked $85. He pays $90.95 including sales tax. What percent sales tax does he pay?

• 6% 7% 5% 6.54% 3% 2. What percent of 90.95 is the sales tax Sam paid?

• Answer:

  1. This problem can be done by a third grader using trial and error just multiply each of the answers given by 85 and add it to 85 and see which sum is 90.95). With algebra, it is done more quickly and neatly. 90.95-85=5.95 so the sales tac is 5.95 x * 85 = 5.95 is an equation for calculating the percent x=5.95/85=.07 (and 100*.07=7, 7%) 2. This problem is similar. The equation is: x * 90.95 = 5.95 x=5.95/90.95=.06542 (6.54%) The reason that the two problems are different, even though they may seem to be asking the same thing, is that problem one is dealing with the tax as a percent of the base cost and problem two is dealing with the tax as a percent of the total (base and tax) cost.