Question

The cost of 3 pens and 2 copies Rs.110. represent this situation with a linear equation in two variables. also, find the cost of one copy if one pen costs Rs.20.

Answer 1

let the no. of pens be x
and no.of copies be y
then the total cost of all the material bought is 110 rs
then the equation will be, 
3x+2y=110
it is the equation.

given 1 pen costs 20rs
so x=20
3(20)+2y=110
60+2y=110
2y=110-60
2y=50
y=50/2
y=25
therefore cost of 1 copy=rs 25

Answer 2

let the cost of each pen be=x
and cost of each copy be=y

by the question,
3x + 2y =110

cost of each pen (x)=rs.20.....(given)

therefore,
3(20)+2y=110
⇒60+2y=110
⇒2y=110-60
⇒2y=50
⇒y=25

therefore cost of each copy is rs.25