Question

In the year $2013$, Pravin saves Rs. $1$ on the first day, Rs. $3$ on the second day, Rs. $5$ on the third day and so on. Find the total amount of his saving in that year.

• A. Rs. $133225$
• B. Rs. $132225$
• C. Rs. $123225$
• D. Rs. $134225$

Answer 1

The correct option is A Rs. $133225$

Pravin saves Rs. 1 on first day, Rs. 3 on second day, Rs. 5 on third day and so on.

There are total $365$ days in the year 2013.

Saving of first day $=1=2\times 1-1$

Second day $=3=2\times 2-1$

Third day $=5=2\times 3-1$ .........................

Saving for last day(${365}^{th}$ day) $=2\times 365-1$.

Total saving amount $=1+3+5+7+....................+(2\times 365-1)$

$=1+3+5+7+..................+(2n-1)=n^2$

$={365}^2=133225$.

Hence, the total saving is Rs. $133225$.