Question

4. In a competitive examination, (+4)

Answer 1

Answer:

(a) 12 incorrect answers

(b) 17 incorrect answers

Explanation:

Given

$Correct = +4$

$Wrong = -2$

$Unattempted = 0$

Let the correct answer be x,

incorrect answers be y

unattempted be z

So, the equation is:

$Marks = 4x - 2y + 0 * z$

$Marks = 4x - 2y$

Solving (a):

Given

$Marks = 20$

$x = 12$

Required

Calculate y

$Marks = 4x - 2y$ becomes

$20 = 4 * 12 - 2 y$

$20 = 48 - 2 y$

Collect like terms

$2y = 48 - 20$

$2y = 28$

$y = 12$

Solving (b):

$Marks = -6$

$x = 7$

Required

Calculate y

$Marks = 4x - 2y$ becomes

$-6 = 4 * 7 - 2y$

$-6 = 28 - 2y$

Collect Like Terms

$2y = 28 + 6$

$2y = 34$

$y = 17$