Markus scored 85, 92, 82, and 94 on the first four tests of the semester. His teacher has not yet told him his score on his fift
h test, but did tell him that his score on the fifth test is five points lower than the average (arithmetic mean) of all five tests. Which equation could Markus use to determine the score of the fifth test, x?
<span>Call x the score on his fifth test. Then the average (arithmetic mean) of the five test will be: (85 + 92 + 82 + 94 + x) / 5. That is equal to (353 + x ) / 5. The teacher said that the new score, x, is 5 points lower than the average, then x = (353 + x) / 5 - 5 . Answer: Markus could use the equation x = (353 - x)/ 5 - 5 (or an equivalent form of it) </span>
20 mysteries. Add 20% and 30% to get 50%. Then rewrite 50% as 50/100. Next multiply 50/100 by 40 to get 2,000/100.The last thing to do is simplify to get 20 and subtract 20 from 40 to get 20 mysteries.
