Jacob has a mean score of 78 after his first four math tests. He wants to make a B, or an average of 80, in math. What does he need to score on the fifth test to have a mean score of 80? (1 point) Responses 82 82 88 88 94 94 108

1 answer

To find out what Jacob needs to score on his fifth test to achieve a mean of 80, we can start by calculating the total score he needs after five tests.

  1. Calculate the total score needed for a mean of 80: \[ \text{Total score needed} = \text{Mean} \times \text{Number of tests} = 80 \times 5 = 400 \]

  2. Calculate Jacob's current total score after four tests: Given that his mean score after four tests is 78: \[ \text{Current total score} = \text{Mean} \times \text{Number of tests} = 78 \times 4 = 312 \]

  3. Find out what he needs on the fifth test: We can determine the score needed on the fifth test by subtracting his current total score from the total score needed: \[ \text{Score needed on fifth test} = \text{Total score needed} - \text{Current total score} = 400 - 312 = 88 \]

So, Jacob needs to score 88 on his fifth test to achieve an average of 80.