SOLUTION: terry did all 25 problems on his test and got an 85. scores are computed by giving 4 points for each right answer and subtracting one for each wrong answer. how many problems did t

Question 597014: terry did all 25 problems on his test and got an 85. scores are computed by giving 4 points for each right answer and subtracting one for each wrong answer. how many problems did terry get right and wrong?
Answer by math-vortex(648) (Show Source): You can put this solution on YOUR website!
Hi, there--
.
Let x be the number of problems Terry got right.
Let y be the number of problems Terry got wrong.
.
Since a right answer adds 4 points, the number of points for right answers is 4x.
Since a wrong answer subtracts 1 point, the number of points for wrong answers is -y.
.
The total number of problems (right and wrong) is 25, so

.
The total score (points for right answers minus points for wrong) is 85, so

.
Solve the system of equations using substitution. Rewrite the first equation in terms of y.

.
Substitute 25-x for y in the second equation.

.
Simplify.

.
Terry has 22 right answers.
Terry has 25-22=3 wrong answers.
.
CHECK
Does this combination give a score of 85? 22*4=88 and 3*(-1)=-3. 88-3=85...YES!
.
That's it. Feel free to email via gmail if you have questions about this solution.
.
Ms.Figgy
math.in.the.vortex@gmail.com
RELATED QUESTIONS
Terry did all 25 problems on the test and got an 85. Scores are computed by giving 4... (answered by Earlsdon)

Terry did all 25. Questions on the test and got and 85% scores are computed by giving 4... (answered by stanbon)

This is a 5th grade math problem that I heard from a friend and I am curious to learn the (answered by stanbon)

pls. help me to answer: a test is composed of 25 questions. the score of examinee is... (answered by greenestamps)

A class has an equal number of boys and girls. The boys all got 85% on a test and the... (answered by robertb)

I had a test of 46 questions: one question equaled 4 points, a second question had 5... (answered by lynnlo)

The well-known psychologist Dr. Elbod has established what he calls his Generalized... (answered by ikleyn)

Hi, I have been assigneda rather large piece of homework that is mostly easy, however it... (answered by stanbon)

The least-squares regression equation for our data is �hat" y = 8.44 - 0.33x . with 3... (answered by ikleyn)