Unfair Loss in Savings of Life

On his 20th birthday, Ajay started depositing Rs.500 in his saving box. His brother Vijay used to withdraw Rs.100 from the same box on his birthday every year. On his 60th  birthday, Ajay opens his box & finds only Rs.1000 in it.

How this could be possible?

Ajay & Vijay

This is how it's possible 

Having Birthday On Leap Day

What was looking impossible?

Since Ajay celebrates his birthday on 29th February, he used to deposit Rs.500 in saving box once in 4 years. From age 20 to 60, he celebrated only 10 birthdays saving only 500 x 10 = 5000. 

But Vijay withdrawing Rs.100 every year means he took 100 x 40 = 4000 so far.

That's why only 5000 - 4000 = 1000 left in the box.