Question

how to solve this question?

Answer 1

let 10rupee note be x
and 20 rupee note be y
Now Case-1
x+y=50
x=50-y
Now case 2
10x+20y = 800
10(50-y) + 20y = 800
500-10y+20y = 800
10y=300
y=300/10
y=30
Now,
x=50-y
x=50-30
x =20