# math

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Tim wants his mean (average) quiz score in history class to be 90. His first 3 quiz scores were 86, 92, and 94. What score should he make on the 4th quiz in order to have a mean (average) quiz score of exactly 90?

I really need the answer ! PLZ PLZ PLZ ! cant figure it outtt !!!! -___-

• math -

Nvmd yo ! I got it !

• math -

x1 + x2 + x3 = 86 + 92 + 94 = 272

( x1 + x2 + x3 + x4 ) / 4 = 90

( 272 + x4 ) / 4 = 90 Multiply both sides by 4

272 + x4 = 90 * 4

272 + x4 = 360

x4 = 360 - 272 = 88

• math -

Tim wants his mean (average) quiz score in history class to be 90. His first 3 quiz scores were 86, 92, and 94. What score should he make on the 4th quiz in order to have a mean (average) quiz score of exactly 90?

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