Carcass wrote:

Camille's average on her 6 math tests this marking period is 75. Fortunately for Camille, her teacher drops each student's lowest grade, and this raises her average to 85.What was her lowest grade?

A) 20

B) 25

C) 30

D) 40

E) 50

We know that the sum of her scores is 6 x 75 = 450. From this total, one score (let’s call it n) will be dropped, leaving (450 - n) as the new sum. We know that because of the dropped score that the new average is calculated with the 5 remaining scores, and the new average is 85. We can create the equation:

[(6 x 75) - n]/5 = 85

450 - n = 425

25 = n

Answer: B

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