Answer:
Rs. paise
x y
-
7 20
(x-1-7) (100+y-20)
x-8 y+80
x-8 = 3y
y+80 = 3x
x = 29
y = 7
x+y = 36
I have actually made two columns one for Rupees one for Paise! Here messed up that format! Anyway, I divided it into Rupees and Paise separately instead of converting the entire thing into paise! That way we are getting two variable but only one eqation.