Question

question no. 3
solve this urgent plz

Answer 1

let no of right ans be x and wrong be y

3x-y=40=6x-2y=80(1)

4x-2y=50(2)

(1)-(2)

2x=30

x= 15

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

so no. of questions = x+y=20

Answer 2

here is your answer...
even with cross multiplication