You have an absolutely brilliant child who is six years old and will be attending a private college in twelve years. You know that a four-year college now costs at least $30,000 per year, including tuition, books, and room and board. The cost of sending a child to college has increased by 7 percent per year, and you believe this will be true for the next twelve years. How much will the annual tuition be when your child is eighteen

$270,263

Explanation:

Costs = $30,000 per year

Cost  for 4 years  = $30000*4 = $120,000

A = P(1+r/100)^n

A = 120000*(1+0.07/100)^12

A = 120000*2.252191

A = 270262.92

A = $270,263

Therefore, the annual tuition when the child is eighteen will be $270,263.

If you would like to find the step where Betty first made an error, you can do this using the following steps:

Step 1: ($52.65 * 5 weeks + $46.25 - $16.25) * 1/6 = (52.65 * 5 + 46.25 - 16.25) * 1/6
Step 2: ($263.25 + $46.25 - $16.25) * 1/6 = (263.25 + 46.25 - 16.25) * 1/6
Step 3: $293.25 * 1/6 = 293.25 * 1/6
Step 4 : $48.875 = $48.88

Betty first made an error in step 4 (she multiplied 293.25 by 6 and not by 1/6).