Question

A boy scores 3marks for each correct answer and loses 2marks for each incorrect sum he does 24 sum and scores 37marks. How many sums are correct?

Answer 1

Step-by-step explanation:

Correct sums = x (3-marks)

Incorrect sums = y ((-2)-marks)

x + y = 24

3(x + y - 24 = 0)

3x + 3y = 72 ......(A)

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

Elimination method:

5y = 35

y = 35/5

y = 7

Incorrect answers = 7

Correct answers:

x = 24 - y

x = 24 - 7

x = 17