Maths-average score

Sally has a maths test every 2 weeks. The test is out of 25. See below her scores over the past 10 weeks. She is allowed to discount her lowest score when finding her average score, however this means she will also have to discount her highest score.

Which of the following statements is true?

A. Sally’s average when discounting her highest and lowest score is more than 1% higher than when she does not
B. Sally’s average when discounting her highest and lowest score is more than 1% lower than when she does not
C. Sally’s average when discounting her highest and lowest score is less than 1% higher than when she does not
D. Sally’s average when discounting her highest and lowest score is less than 1% lower than when she does not
E. Sally’s average is the same whether she discounts the scores or not
Correct D