Question

A science test, which is worth 100 points, consists of 24 questions. Each question is worth either 3 points or 5 points. If x is the number of 3-point questions and y is the number of 5-point questions, the system shown represents this situation.

x + y = 24

3x + 5y = 100

What does the solution of this system indicate about the questions on the test?

The test contains 4 three-point questions and 20 five-point questions.
The test contains 10 three-point questions and 14 five-point questions.
The test contains 14 three-point questions and 10 five-point questions.
The test contains 20 three-point questions and 8 five-point questions.

Answer 1

10 three-point questions and 14 five-point questions.

Explanation:

x+y = 24

3x+5y = 100

We can solve this system of equations using elimination. In order to do this, let's first multiply the first equation by 3...

3x+3y=72

3x+5y=100

Now, subtract the first equation from the second equation...

2y=28

Divide both sides by 2

y=14

Plug this back into any of the equations to solve for x...

x+14=24

x=10

There were 10 three-point questions and 14 five-point questions