After his first six biology tests, Ruben has a mean score of 78.What score does Ruben need on the next test to raise his average (mean) to 80?
7 * 80 = 560
He needs a total of 560.
6 * 78 = 468
He has a total of 468.
560 - 468 = ______ score he needs on next test.
Let's calculate the score Ruben needs on the next test to raise his average to 80.
To raise his average from 78 to 80, Ruben would need to increase the total sum of his scores by 2 points, since the average is the sum of scores divided by the number of tests.
Ruben has already taken 6 tests, so the total sum of his scores is 78 * 6 = 468.
To raise the average to 80, the new total sum of his scores should be 80 * (6 + 1) = 560.
Therefore, Ruben needs to score 560 - 468 = 92 on the next test to raise his average to 80.
To find out the score Ruben needs on the next test to raise his average to 80, we can use the concept of mean (average).
The mean score of a set of numbers is calculated by summing all the numbers and dividing the total by the count of numbers.
Given that Ruben has already taken 6 biology tests, we know the sum of his scores is 78 x 6 = 468.
To raise his average to 80, we need to consider the total number of tests (including the next one) and the desired average.
Ruben will have taken 7 tests in total (6 previous tests + 1 upcoming test).
To calculate the sum of all 7 test scores required to achieve an average of 80, we multiply the desired average (80) by the total number of tests (7):
80 x 7 = 560
Now, to find out the score Ruben needs on the next test, we subtract the sum of previous test scores (468) from the sum of all 7 test scores (560):
560 - 468 = 92
Therefore, Ruben needs to score a 92 on the next test to raise his average to 80.