the average score of five tests was 83. the first four scores were 91, 78, 86, and 72. what was the score of the fifth test? How do I solve this, and what is the answer? Thanks :D
91 + 78 + 86 + 72 + x = 5 * 83
To find the score of the fifth test, we can use the formula for the average:
Average = (Sum of all scores) / (Number of scores)
In this case, we are given the average score of five tests, which is 83. We are also given the first four test scores: 91, 78, 86, and 72.
To find the sum of all five scores, we can add up the four given scores and the unknown score of the fifth test:
Sum of all scores = 91 + 78 + 86 + 72 + (Score of the fifth test)
We know that the average is 83, so we can set up an equation using the formula for average:
83 = (Sum of all scores) / 5
Substituting the sum of all scores, we have:
83 = (91 + 78 + 86 + 72 + (Score of the fifth test)) / 5
Now we can solve for the score of the fifth test by rearranging and isolating the unknown variable:
83 = (327 + (Score of the fifth test)) / 5
Multiply both sides of the equation by 5:
415 = 327 + (Score of the fifth test)
Subtract 327 from both sides:
415 - 327 = Score of the fifth test
88 = Score of the fifth test
Therefore, the score of the fifth test is 88.