Question

Amritha bought some pens for Rs 360 . When the price of each was reduced by Rs 3 , she could buy 6 more pens for the same cost of Rs 360. Find the original cost of the pen.

Answer 1

let,no of pen is x

and cost of pen is y

from the first condation

xy=360

from the sec cond

(y-3)(6+x)=360

y(6+x)-3(6+x)=360

6y +xy-18-3x =360

put xy=360

6y+360-18-3x=360

6y+ 342-3x=360

-3x+6y=18take 3common

-x+y=6

put x=360/y

-360/y+y=6

y=6y/360