Spend & Balance: where did the one rupee gone?

Question

Answer 1

Two two column has no relation, to prove lets do the similar calculation where your are spending 10 Rs per day then we have something like

Spend Balance 
10     40
10     30
10     20
10     10
10      0
----------
50    100

Now see we have a difference of 50 now, so in short these two columns are not related so cant be compared.