Multiple choice

Rachna had an average score of $45$ from $6$ test. Her teacher dropped her lowest score, which is $30$ and calculated the average of the remaining scores to decide her grade. Which of the following gives her new average score?

  1. $\cfrac { \left( 45\times 5-30 \right) }{ 5 } $
  2. $\cfrac { \left( 45\times 5-30 \right) }{ 6 } $
  3. $\cfrac { \left( 45\times 6-30 \right) }{ 5 } $
  4. $\cfrac { \left( 45\times 6-30 \right) }{ 6 } $
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C Correct answer
Explanation

The sum of the 6 scores is 45 * 6. After removing the score of 30, the new sum is (45 * 6) - 30. Since there are now 5 scores remaining, the new average is ((45 * 6) - 30) / 5.

AI explanation

Using the average formula, Rachna's total score for all 6 tests is 45 multiplied by 6, which equals 270. After dropping her lowest score of 30, the sum of her remaining 5 scores is 240. The new average is this remaining sum divided by 5, making the correct expression (45 x 6 - 30) / 5.

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