Question

The cost of a pen is RS. 4 more than cost of a note book . The total cost of 4 pens and 6 note books is RS. 106. Find the cost of one pen and one note book

Answer 1

let pen be x and notebook be y
from 1st condition
$x - 4 = y.....1$
from 2nd condition
$4x + 6y = 106....2$
substitute 1 in 2
$4x + 6(x - 4) = 106 \\ 4x + 6x - 24 = 106 \\ 10x = 130 \\ x = 13$
put x=13 in 1
$13 - 4 = y \\ y = 9$
cost of one pen and one notebook
x+y
13+9
22