The local skating rink pays marry a fixed rate per pupil plus a base amount to work as a skating instructor. she earns $90 for i
nstructing 15 students on Monday afternoon. last Friday, she earned $62 for working with 8 students. Lisa is also a skating intructor. She receives half of the base amount that Mary does, but she is paid twice as much per student. Who would earn more money instructing a class of 20 students?
Begin by creating a system of equations: let 'a' represent the amount Mary earns per student, and 'b' denote her fixed amount. The equations are 90=15a+b (subtracting the lower from the upper equation) and 62=8a+b. From these, we have 90-62=28, leading to 15a-8a=7a, and b cancels itself out. This gives us 7a=28, resulting in a=4. Substituting 'a' into 62=8a+b reveals b=30. Since Lisa earns half of Mary's base, her fixed amount is 15, but she makes twice as much per student, bringing her rate to 8 per student. Thus, we can formulate: m=4c+30 for Mary's earnings, and l=8c+15 for Lisa's. Setting c=20 results in m=110 and l=175, showing that Lisa makes more when teaching a class of 20 students. I trust this information helps.
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