Shonda's 6 test scores have an arithmetic mean of 78%. After removing 1 test score, the new arithmetic mean of the 5 remaining scores is 84%. Which test score was removed?

48

Step-by-step explanation:

Let the scores be a, b, c, d, e, f.

So sum of these scores = mean * 6

= 78 X 6

After say removing test score a, mean = 84 %

So sum of these remaining scores = mean * 5

= 84 X 5

Having calculated these two, the removed score = difference of the two sums.

So removed test score = 78 X 6 - 84 X 5

= 48