Question

0.
5. A boy gets 3 marks for each correct sur
loses 2 marks for each incorrect sum. He
24 sums and obtains 37 marks. The nur
of correct sums were:​

Answer 1

Answer:

Let the number of correct sums be x and the number of incorrect ones be y.

Then,according to the question

x+y=24 ....(1)

(he attempted 24 questions in total)

3x−2y=37 ..(2)

(he gets 3 marks for correct sum and loses 2 marks for wrong sum)

Multiplying (1) by 2 and adding it to (2).

2x+2y+3x−2y=48+37

5x=85

x=17

From (1),

17+y=24

y=7

He did 17 correct sums