# On which day of the month is his birthday?

+1 vote
124 views

As Mohan's birthday approaches , he likes to save up to to treat himself.
On the first day of the month he saves Rs 1, on the second day he saves 2, on the third day 3 and so on.
On his birthday he will have saved a total Rs 153.
On which day of the month is his birthday?

posted Dec 20, 2018

+1 vote

18

Days- x,
Sum of x days calculated by a formula: Sx=x*(x+1)/2,
x*(x+1)/2=153,
The positive solution is x=18

Similar Puzzles

I engaged in a strange activity. My birthday was approaching and I decided to collect money for my birthday bash. On the first day of the month, I kept a dollar in my piggy bank, on the second, I kept two dollars and on the third, I kept three and so on.

On my birthday, I had a total of 276 dollars in my piggy bank.
Can you find out on which day of the month was my birthday?

+1 vote

Phil asks his friend Stan when his birthday is. Stan replies that he was 32 the day before yesterday and next year he’ll be 35. When is his birthday and how is this possible?