Question

Scores are 78,81,83, and 76 what must she earn on the fifth test to earn an average test score of 81

Answer 1

87%.
Because:
1) 78+81+83+76+87=405
2) 405/5=81
You add up all the test scores and then divide by 5 because thats how many test there are.

Answer 2

The average value of a data set is equal to the sum of each entry divided by the number of entries. In this case, we have 5 scores, so we can find set up the following equation where x is the fifth score:


`(78+81+83+76+x)/(5) = 81`

Now solve for x:


`78 + 81 + 83 + 76 + x = 81(5)`


`318 + x = 405`


`x = 87`

The fifth score must be 87.