Question

three pencils and four pen cost rupees 270 while four pencil and three pens cost Rs 150 find the combined cost of pencil and pen

Answer 1

let the pencils =x
" " pens=y
ATQ
3x+4y=270 ×4 ...1
4x+3y=150 ×3 ...2

12x+16y=1080
12x+9y=450 (subtracting)
-------------------
y=630 ....3
put equation 3 in 2

4x+3 (630)=150
4x=150-1890
x= -1740/4
= -437.5
x+y=?
630-437.5=192.5