Posted by keke on Tuesday, May 29, 2012 at 5:38pm.
mike has an average of 89 on the five tests he has taken so far this semester. what grade must mike earn on the next test to raise his average grade exactly to 90?

math  Ms. Sue, Tuesday, May 29, 2012 at 5:43pm
5 * 89 = 445
600 * 0.9 = 540
540  445 = 95

math  Bosnian, Tuesday, May 29, 2012 at 6:39pm
( x 1 + x 2 + x 3 + x 4 + x 5 ) / 5 = 89 Multiply both sides by 5
x 1 + x 2 + x 3 + x 4 + x 5 = 89 * 5 = 445
( x 1 + x 2 + x 3 + x 4 + x 5 + x 6 ) / 6 = 90
( 445 + x 6 ) / 6 = 90 Multiply both sides by 6
445 + x 6 = 6 * 90 = 540
x 6 = 540  445 = 95
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