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 About the author Remi
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! Reply
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 Reply
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!
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