Question

plzzz... help.....in que 21......from chapter linear equation in two variables.......(need solution)

Answer 1

the marks Jayanthi got is 90. So 90=1x-1/2y. the total number of questions Jayanthi answered 120 questions. So 120=x+y. solving we get y as 20 and x as 100

Answer 2

Let the number of correct answers = x
number of wrong answers = y

Now,
Jayanthi answered totally 120 questions. Writing in equational form.
x + y = 120……(1)

We know that correct answers award 1 mark.
Wrong answers award 1/2 mark.
1(x)-1/2y = 90

x-1/2y =90

2x-y =180.

Now we have two equations ;

x + y = 120 …(1)

2x - y =180 …(2)
===============
3x = 300

x = 100

Number of correct answers =100.

Number of incorrect answers =20

:" Therefore, Jayanthi answered 100 questions correctly :"