SOLUTION: in an examination consisting of 15 questions,8 marks are awarded for a correct answer and 4 marks are deducted for a wrong answer,how many correct answer are needed to score 72 mar

Question 870020: in an examination consisting of 15 questions,8 marks are awarded for a correct answer and 4 marks are deducted for a wrong answer,how many correct answer are needed to score 72 marks in this examination?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
correct answer-----------x
wrong answer-------------y
x+y=15
8x-4y=72
1.00 x + 1.00 y = 15.00 .............1
Total value
8.00 x -4.00 y = 72.00 .............2
Eliminate y
multiply (1)by 4.00
Multiply (2) by 1.00
4.00 x 4.00 y = 60.00
8.00 x -4.00 y = 72.00
Add the two equations
12.00 x = 132.00
/ 12.00
x = 11.00
plug value of x in (1)
1.00 x + 1.00 y = 15.00
11.00 + y = 15.00
y = 15.00 -11.00
y = 4.00
y = 4.00
11 correct answers
RELATED QUESTIONS
in a examination one marks is awarded for every correct as and 1/4 marks is deducted for... (answered by JBarnum)

There are 20 questions in a short test. 5 marks are awarded for every correct answer, but (answered by tsewaitung)

In an examination a student scores 1 mark for each correct answer and 0.25marks are... (answered by tommyt3rd)

A Mathematics competition contests of 30 multiple-choice questions. 4 marks are awarded... (answered by Theo)

an examination paper consists of 40 questions. 5 marks are given for each correct... (answered by Electrified_Levi)

in an examination , a student attempted 15 questions correctly and secured 40 marks. if... (answered by ewatrrr)

here were 30 questions in a mathematics competition. all questions must be answered. 5... (answered by lwsshak3)

A test contains 200 multiple choice questions. The marking rule is designed such that 2... (answered by macston)

In a multiple choice test, two marks are given for each correct answer and one mark is... (answered by stanbon)