A student has gotten the following grades on his tests. What is the minimum grade he must get on the last test in order to have an average of 82 ? 85 , 90 , 79 , 72

84

Step-by-step explanation:

The average is found by adding all the scores together and dividing by the number of scores

Let the unknown score be x

(85+90+79+72+x) / 5 = 82

Multiply each side by 5

(85+90+79+72+x) / 5*5 = 82*5

(85+90+79+72+x) = 410

Combine like terms

326+x = 410

Subtract 326 from each side

326+x-326 = 410 - 326

x = 84

84

Step-by-step explanation:

Because average is basically the mean, so i used a mean calculator and put in the four grades (numbers) and got an average of 81.5, so then i kept putting an additional other number in and wasn't getting 82, until i put in 84 and all of those numbers together gave me an average of 82.