Question

Use a system of linear equations with two variables and two equations to solve. 312 students enrolled in a freshman-level chemistry class. By the end of the semester, 7 times the number of students passed as failed. Find the number of students who passed, and the number of students who failed.

Answer 1

We know that 312 students enrolled in the curse, and if we assume that no one deserts, we can infer the equation:

$P+F=312\text{ \lparen1\rparen}$

As P is the passing students and F is the failing students.

From the second statement, 7 times the number of students passed as failed, we can infer the equation:

$F=7P\text{ \lparen2\rparen}$

With the same meaning of the variables.

Then we can replace F in (1), we have:

$P+7P=312$$P=39$

And from (2):

$F=39\times7=273$

Then the correct answer would be:

Passing students: 39

Failing students: 273