Last Updated on May 4, 2023
GMAT OFFICIAL GUIDE PS
Solution:
We start by creating a variable for the total number of students in the math course. We can say:
T = Total number of students in the math course
Next, we can use variable T in an equation that we translate from the given information. We are given that, of the final grades received by the students in a certain math course, 1/5 are A’s, 1/4 are B’s, 1/2 are C’s, and the remaining 10 grades are D’s. Since this represents all the grades in the class, it represents all the students in the class. Thus we know:
number A’s + number B’s + number C’s + number D’s = Total number of students in the class
1/5(T) + ¼(T) + ½(T) + 10 = T
We can multiply the entire equation by 20 to cancel out the denominators of the fractions and we have:
4T + 5T + 10T + 200 = 20T
19T + 200 = 20T
200 = T
There are a total of 200 students in the math class.
Answer: D
