Answer:
94
Step-by-step explanation:
Let the unknown number be denoted by the variable, x. Also note that, the average can be found by adding all values together and dividing by the amount of values there are.
Set the equation:
(85 + 73 + 92 + 66 + x)/5 = 82
Isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Simplify first by combining like terms, and then do the opposite of PEMDAS.
PEMDAS is the order of operations, and stands for:
Parenthesis
Exponents (& roots)
Multiplications
Divisions
Additions
Subtractions.
Combine like terms:
(85 + 73 + 92 + 66 + x)/5 = 82
(316 + x)/5 = 82
Next, isolate the x, by multiplying 5 to both sides of the equation:
(316 + x)/5 * 5 = (82) * 5
316 + x = 82 * 5
316 + x = 410
Lastly, subtract 316 from both sides of the equation:
x + 316 = 410
x + 316 (-316) = 410 (-316)
x = 410 - 316
x = 94
94 is the final test score.
