To calculate averages you must first add all the test scores.
add 82, 90, 78, 76 and 94.
next choose one of the options and add it on to the sum that you got from the original test scores
now divide the whole thing by how many trials there were (how many tests were done). in this case, including the option, 6 trials were completed so divide by 6.
if the answer is not 86, then repeat for other options until you get 86
