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?
80 * 5 = 400
78 * 4 = 312
400 - 312 = 88
To find out what Jacob needs to score on the fifth test, we can use the concept of the mean (average). The average of the five test scores should be 80.
Let's breakdown the solution step by step:
Step 1: Calculate the sum of the first four test scores.
Since Jacob's mean score after the first four math tests is 78, we can multiply the mean score by the number of tests to find the sum.
Sum of the first four scores = 78 * 4 = 312
Step 2: Calculate the sum of all five test scores.
To have a mean score of 80, the total sum of all five scores should be: sum of the first four scores + score on the fifth test = 312 + score on the fifth test
Step 3: Set up an equation and solve for the score on the fifth test.
To find the score Jacob needs on the fifth test, we can set up the equation:
(312 + score on the fifth test) / 5 = 80
Simplifying the equation:
312 + score on the fifth test = 80 *5
312 + score on the fifth test = 400
Step 4: Solve for the score on the fifth test.
(score on the fifth test) = 400 - 312
(score on the fifth test) = 88
Therefore, Jacob needs to score 88 on the fifth test to have a mean score of 80.
To find out what Jacob needs to score on his fifth test to achieve an average of 80, we can set up an equation.
Let's assume the score Jacob needs to achieve on the fifth test is "x".
The sum of his scores after the five tests would be: 78 + x.
Since Jacob wants his average to be 80, we can set up the equation:
(78 + x) / 5 = 80.
To solve for x, we'll start by multiplying both sides of the equation by 5 to eliminate the denominator:
78 + x = 400.
Now, we can isolate x by subtracting 78 from both sides of the equation:
x = 400 - 78.
Calculating the right side of the equation:
x = 322.
Therefore, Jacob needs to score at least 322 on his fifth math test to achieve an average of 80.