Question 452131
The Average (arithmetic mean) of a student's scores on 4 tests was 77.
 If he recieved a score of 69 on each of the first two tests and an 82 on the
 third, what was his score on the fourth test?
:
let x = fourth test score
:
{{{(2(69) + 82 + x)/4}}} = 77
:
{{{(220 + x)/4}}} = 77
multiply both sides by 4
220 + x = 4(77)
x = 308 - 220
x = 88 on the 4th test
:
:
You can check this
{{{(69 + 69 + 82 + 88)/4}}} =