Siri bought 2 notebooks and 3 pens for Rs 90 . Lakshmi bought

4 notebooks and 5 pens for Rs 140. Form linear equations

Question

Siri bought 2 notebooks and 3 pens for Rs 90 . Lakshmi bought

4 notebooks and 5 pens for Rs 140. Form linear equations for the given

situation to find the cost of a pen and a notebook​

in progress 0
Remi 3 months 2021-07-21T02:22:51+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-07-21T02:24:01+00:00

    taking the number of notebooks as x and pens as y

    (2x+3y=90)×5

    (4x+5y=140)×-3

    ⬇️

    10x+15y=450

    -12x-15y=-420

    ———————-

    -2x=30

    X=30÷-2= $-15 price of notebooks

    substituting the value of x in eq 1

    2x+3y=90

    2(-15)+3y=90

    -30+3y=90

    3y=90+30

    y=120÷3

    =$40 is the price of no pens

    I tried but hope this helps!

    0
    2021-07-21T02:24:13+00:00

    Answer:

    let the cost of one copy and one pen be x and y

    As per question

    2x + 3y = 90 (i)

    4x + 5y = 150 (ii)

    by substitution method we get

    x = 90 -3y ÷ 2 iii

    put equation iii in ii we get

    4(90-3y÷2) + 5y =150

    360-12y÷2 +5y =150

    360 -12y +10y = 300

    360 -2y = 300

    -2y =-60

    y =60÷2

    y = 30 iv

    put equation iv in eq i

    2x + 3(30) =90

    2x+90 = 90

    2x = 90-90

    2x = 0

    x= 2

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