Question

A boy gets 3 marks for each correct sum and looses 2 marks for each incorrect sum . He does 24 sums and obtains 37 marks . How many of correct sums were there ?

Answer 1

Answer:

17 correct sums.

Step-by-step explanation:

Let,

The no. of each correct answer =x

The no. of each wrong answer =y

According to the Question:-

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

Again,

According to the Question:-

3x - 2y =37 ------(2)

Multiple 3 in equation (1)

3x - 3y =72 -------(3)

By Elimination method in equation (2) and (3) :-

3x + 3y = 72

3x - 2y = 37

- + -

-----------------------

5 y = 35

y = 35 ÷ 5

y = 7

put this in equation (2)

3x - 2y = 37

3x - 2(7) = 37

3x - 14 = 37

3x = 37 + 14

3x = 51

x = 51 ÷ 3

x = 17

He did 17 Correct Sums.

Hope it helps you...

Thank you

Answer 2

Answer:

17 is a correct answer

Step-by-step explanation:

I hope all student understand