A student took 5 tests this marking period and had a mean score of 90. Her scores on the first 4 tests were 90, 96, 86, and 92. What was her score on the fifth test?
You can always treat such examples as an equation; (90+96+86+92+X)/5=90 X is the desired score, 5 is the number of tests. As you can see, it is the usual equation for getting the mean value which the sum of the values over their number. now; 90+96+86+92+X=90*5 X=90*5-(90+96+86+92) X=86. Hope this helps.
