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
___________ >
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.
4 X 85 = 340
75+85+90+ X= 340
250 + X= 340
X=90
The equation you provided is used to calculate the final grade in the class. The numerator of the fraction represents the sum of all the grades she has received so far in the class, which are 75, 85, and 90. The variable X represents the unknown test score that she has not taken. The denominator of the fraction is simply the total number of grades she has received so far, which is 4.
To solve for the unknown test score, we can start by simplifying the equation:
(75 + 85 + 90 + X) / 4 > 85
Next, we multiply both sides of the inequality by 4 to eliminate the fraction:
75 + 85 + 90 + X > 85 * 4
Now, we can simplify the equation further by adding the known grades:
250 + X > 340
To solve for X, we subtract 250 from both sides of the inequality:
X > 340 - 250
X > 90
Therefore, in order to get an 85 in the class, Jane needs to score higher than 90 on her final test.