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?
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}.
To find the score Jacob needs to achieve on his fifth test in order to have a mean score of 80, we can set up an equation based on the given information.
Let's say Jacob wants to score x on his fifth test.
The sum of his scores after the fifth test will be (4 tests' total + x).
His mean score after the fifth test will be [(4 tests' total + x) / 5].
According to the given information, his mean score after the first 4 tests is 78. So we can set up the equation:
(4 tests' total) / 4 = 78
Simplifying this equation, we get
4 tests' total = 78 * 4
4 tests' total = 312
Now, we can set up the equation for the mean score after the fifth test:
[(312 + x) / 5] = 80
To find the value of x, we can solve this equation:
312 + x = 80 * 5
312 + x = 400
x = 400 - 312
x = 88
Therefore, Jacob needs to score 88 on his fifth test in order to have an average of 80 in math.
To find out what Jacob needs to score on his fifth math test to have a mean score of 80, we can set up an equation.
Let's assume that Jacob's score on the fifth test is x.
The sum of his scores on the first four tests would be 78 * 4 = 312.
The sum of his scores on all five tests, including the fifth test, would be 80 * 5 = 400.
To find the score Jacob needs on the fifth test, we can subtract the sum of the first four tests' scores from the sum of the five tests' scores:
400 - 312 = 88
Therefore, Jacob needs to score 88 on his fifth math test to have a mean score of 80.