Question

One day Siri went to a book shop with her father and bought
3 notebooks and 2 pens. Her father paid 80 for them. Her friend Laxmi
liked the notebooks and pens so she bought 4 notebooks and 3 pens of the D
same kind for 110 and again her classmates Rubina liked the pens and
Joseph liked the notebooks. They asked Siri the cost of one pen and one notebook. But, Siri did
not know the cost of one notebook and one pen separately. How can they find the costs of these
items?by modal method​

Answer 1

Step-by-step explanation:

let notebook be x

and pens be y

3x+2y=80----(1)

4x+3y=110----(2)

now by elimination method

4(3x+2y=80)=12x+8y=360-(3)

3(4x+3y=110)=12x+9y=330-(4)

now eliminate (4) from (3)

12x+8y-360-(12x+9y-330)

=>17y-30=0

=>17y=30

=y=30/7=4.28

substitute y in eq(1)

3x+2(4.28)=80

3x+8.56=80

=3x=71.44

=x=71.44/3=28.3