Question

ex .3.5 ques no.4 part 3 class 10​

Answer 1

Let number of correct answers be x and number of incorrect answers be y.

As per given conditions,

3x - y = 40 … (1)

4x - 2y = 50 … (2)

(1)  2  6x - 2y = 80 … (3)

Subtracting (2) from (3), we get,

2x = 30  x = 15

y = 3x - 40 = 45 - 40 = 5

Total number of questions in the test = 15 + 5 = 20

Hope this helps!! If you want a detailed explanation, comment on this answer. I will explain in the comments