Question 1168887
she paid 20 dollars each time they came and they came 17 times.
the cost was 20 * 17 = 340.
she paid 390, so it looks like company A had an initial fee of 50 dollars and charged an additional 20 dollars for each visit.


company B had an initial fee of 125 dollars and charged an additional 15 dollars for each visit.


the cost will be the same when 50 + 20 * x = 125 + 15 * x
x represents the number of visits.
subtract 50 from both sides of the equation and subtract 15 * x from both sides of the equation to get:
20 * x - 15 * x = 125  - 50
simplify to get:
5 * x = 75
solve for x to get:
x = 15
the cost will be the same when 15 visits have been made.
company A will charge 125 + 15 * 15 = 350 dollars.
company B will charge 50 + 15 * 20 = 350 dollars.


if she expects less than 15 visits, then she should go with company A.
if she expects more than 15 visits, then she should go with company B.


for example:
at 10 visits:
company B would charge 125 + 10 * 15 = 275
company A would charge 50 + 10 * 20 = 250
company A would be cheaper.


at 20 visits:
company B would charge 125 + 20 * 15 = 425
company A would charge 50 + 20 * 20 = 450
company B would be cheaper.


they equations can be graphed.
in that way you can visualize where the break even point is and which company is better before the breaking point and which company is better after the breaking point.


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