Question

if the price of pen decreases by 20%, then a man can buy 10 more pens for rs 100. what is the new price (in rs) of each pen?

Answer 1

Therefore according to question

x*y=100...........................(1)

and

(0.8*y)*(x+10)=100............(2)

By equation 2,

(0.8)*x*y+8*y=100

Using question 1

(0.8)*(100)+8*y=100
8*y=20
y=2.5

Therefore the new price is (0.8)*y=0.8*2.5=2

Hence the price of pen is Rs.2