Question

Michael gets 3 marks for each correct questions and loses 2 marks for each wrong answers. He attempts 30 sum and obtain 30 marks. Find the no of questions he answered correctly?

Answer 1

Answer:

Let the no. of problems solved correctly be x

Then no. of incorrect questions = (30-x )

MARKS AWARDED FOR CORRECT ANSWERS = 3x

MARKS DEDUCTED FOR INCORRECT ANSWERS = 2 (30-x)

= 60 - 2x

EQUATION FORMED,

3x - ( 60 - 2x ) = 30

3x - 60 + 2x = 30

5x - 60 = 30

5x = 30 + 60

x = 90/5

=> x = 18

THEREFORE,

NO OF CORRECT ANSWERS = 18

NO OF INCORRECT ANSWERS = 12

Mark as brainliest

Answer 2

Step-by-step explanation:

Let the sums attempted correctly be x and the sums attempted wrongly be y.

3x−2y=40 ....(i)

x+y=30 .....(ii)

Multiplying (ii) by 3

3x+3y=90 .....(iii)

Subtracting (i) from (ii), we get

5y=50

⇒y=10

∴x=20