You scored 88, 92, and 87 on three tests. write and solve an equation to find the score you need on the fourth test so that your mean test score is 90.

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Set up the equation to find the average (mean) of four test scores:

88+92+87 + x

          4

We set this equal to the desired average (90) and solve for x.

88+92+87 + x

= 90, or 88+92+87+x = 360.  Next, 267 + x = 360.

          4

Subtracting 267 from both sides, we get x = 93.

Earning a 93 on the last test will result in an overall test score of 90.

my guess would be b and d, but i didn’t actually get out the pen and paper. lol