Jane is taking a class and asks you to help her figure out what her last grade must be in the class to get a 85 in the class. She tells you the following calculation is used to find your final grade:
75+85+90+X
----------- > or = to 85
4
x is her last score which has not been taken. Explain this equation and the process you would use to solve for the unknown test score. Solve for the test score.
Can you please explain the process you used to solve? Thank you
75+85+90+x/4=85
250+x/4=85
250+x= 340
x=90
Certainly! To find out what Jane's last grade must be in order to achieve a final grade of 85 in the class, we can use the given equation:
(75 + 85 + 90 + X) / 4 >= 85
Let's break it down step by step:
1. The equation is written as a fraction: the sum of all the known grades (75, 85, and 90) plus the unknown grade X, divided by the total number of grades, which is 4.
2. The inequality ">= 85" means that Jane's final grade must be greater than or equal to 85 to achieve her desired score.
To solve for the unknown test score X, we can follow these steps:
1. Multiply both sides of the inequality by 4 to eliminate the fraction:
(75 + 85 + 90 + X) >= 85 * 4
2. Simplify the equation:
250 + X >= 340
3. Subtract 250 from both sides of the inequality:
X >= 340 - 250
X >= 90
Therefore, Jane's last grade must be 90 or higher to achieve a final grade of 85 in the class.