algebra one grade 8

Question

fatima earned an 85 average in her science class. The average is based on 6 tests that she takes over the span of the marking period. On her first four tests she earned a 83, a 78 an 87 and an 80. On her sixth test she scored 8 more points than on her fifth test.

Answer 1

Here's another way to do it (not necessarily better).

If the average is 85 on 6 tests, then the total score musr have been 85 x 6 = 510 (just a revised equation for the avg = total/no. of tests).

The total of the 1st 4 tests is 328, so the last two must have totaled to 182.

So we have an equation to solve: x + (x + 8) = 182 (x is the score for the 5th test)

2x + 8 = 182

2x = 174

x = 87 and x + 8 = 95 for the 5th and 6th tests, respectively.

Answer 2

If the question is, "What scores did she receive on her 5th and 6th tests?"

First create an equation with the given information to find the average where x represents her fifth test and (x+8) represents her 6th test:

85 = (83 + 78 + 87 + 80 + x + (x + 8)) ÷ 6

Simplify the equation:

85 = (336 + 2x) ÷ 6

Multiply both sides by 6

510 = 336 + 2x

-336 -336

----------------------

174 = 2x

÷2 ÷2

----------------------

87 = x

(x+8) = 95

She scored an 87 on her 5th test and a 95 on her 6th test.

Hope that helps!