Jacob has a mean score of 78 after his first 4 math test. he wants to make a b or an average of 80 in his math. what does he need to score in the fifth test to have a mean score of 80?

Answer 1

To find out what Jacob needs to score in the fifth test, we need to find the total score he needs to have after five tests.

Jacob's mean score of 78 after the first four tests is the total score divided by 4. Therefore, the total score is 78 x 4 = <<78*4=312>>312.

In order to have a mean score of 80 after five tests, the total score needs to be 80 x 5 = <<80*5=400>>400.

Therefore, Jacob needs to score 400 - 312 = <<400-312=88>>88 on his fifth test. Answer: \boxed{88}.