Vincen wrote: ↑

Sun May 09, 2021 2:04 pm

In a certain history class of 17 juniors and seniors, each junior has written 2 book reports and each senior has written 3 book reports. If the 17 students have written a total of 44 book reports, how many juniors are in the class?

A. 7
B. 8
C. 9
D. 10
E. 11

Answer:A

Source: Official Guide

Here's a boring algebraic approach:
In a certain history class of 17 juniors and seniors...
Since the question asks us to find the number of juniors, let's let x = the number of juniors in the class
Since there are only juniors and seniors, and since there are 17 students in total, we know that 17 - x = the number of seniors in the class

Each junior has written 2 book reports and each senior has written 3 book reports. The 17 students have written a total of 44 book reports
Total number of books written by juniors = 2x
Total number of books written by seniors = 3(17 - x)
So we can write: 2x + 3(17 - x) = 44
Expand: 2x + 51 - 3x = 44
Simplify: -x + 51 = 44
Solve: x = 7

Answer: A

Cheers,
Brent