Question

In an examination Nikita attempted 200 questions and scored 200 marks if every correct answer carried 4 marks and every wrong answer carried -1 mark then find the number of questions answered correctly

Answer 1

Answer:

80 answers were right

Step-by-step explanation:

4x-y=200 ----------1

x+y=200 ; x=200-y --------2

SUBSTITUTING Eq 2 IN 1

we get,

4(200-y)-y=200

800-4y-y=200

-5y=200-800

-y=-600/5

-y=-120

y=120 ----------3

NOW, SUBSTITUTING 3 IN 2

x=200-120

x=80

Answer 2

Answer:

80

Step-by-step explanation:

TOTAL NO OF QUESTIONS=200

MARKS OBTAINED=200

EACH QUESTION CARRIES=4 MARKS

NEGATIVE MARKING =-1

LET THE NO OF CORRECT QUESTIONS BE x

MARKS OBTAINED = EACH QUESTION MARKS *x - 1(200-x)

200 =4 x -1(200-x)

200 =4x -200 +x

200+200=5x

400=5x

400/5=x

x=80...ans