Question

ray carries only 10 rupee and 20 rupee note in his purse.the total amount in his purse in Rs.500. if the total number of notes is 35 ,how many of each kind doea he has

Answer 1

let no of rs.10 be =x
and rs.20 be =y
so x+y = 35
and 10x+20y =500
by using elimination process we can find ans 

Answer 2

let x be the number of 10 rupee note
and y be the number of 20 rupee note
x+y=35. eq-1
10x+20y=500
x+2y=50. eq-2
y=15
x=20