March 2020
Problem of the Month

Test Problems

How many problems must a student get right to score 100 on a 120 question test if the teacher gives one point for each correct answer but subtracts 1/4 point for each wrong answer?

You must show algebra to get credit beginning with LET x = ..., then setting up an equation and solving it.

Solution to the Problem:

The answer is 104 questions.

Let x = number of incorrect answers.
Then 120 - x = number of right answers
(120 - x) - 1/4x = 100
20 = 5/4 x
x = 16 wrong answers, so
120 - x = 104 right answers.

Correctly solved by:

1. Ivy Joseph	Pune, Maharashtra, India
2. James Alarie	Flint, Michigan
3. Brijesh Dave	Mumbai City, Maharashtra, India
4. Bernice Rosales	Delta High School, Delta, Colorado
5. Kelly Stubblefield	Mobile, Alabama
6. Anna T. Vice	Landon School, Bethesda, Maryland
7. Emre Karabiyik	Hacettepe University, Ankara, Turkey
8. Jason Jones	Colorado Springs, Colorado

Send any comments or questions to: David Pleacher