college algebra
posted by Joe on .
Sally took four tests in science class. On each successive test, her score improved by 3 points. If her mean score was 69.5%, what did she score on the first test?

66.5%

thanks for the answer but can you please show how you got that answer

the tests improve by 3 points, therefore:
test 1 x
test 2 x+3
test 3 x+6
test 4 x+9
the mean is the sum of the test scores divided by the number of tests. also, we know the mean = 69.5%
therefore, we get the equation:
(4x+18)/4 = 69.5%
4x+18 = 278
4x = 260
x = 65
therefore the score on the first test was 65%