A bank gives `5%` simple interest per annum. In that bank, Dipubabu deposits `15,000Rs` at the beginning of the year, but withdraws `3000Rs` after `3` months and then again, after `3` months he deposits `8000Rs`. Determine the amount (principal along with interest) Dipubabu will get at the end of the year.

Explanation

`3` months `=(3)/(12)` year `=(1)/(4)` year
Now, simple interest of `Rs15000` in `3` months at the rate of `5%` per annum
`=Rs(150000xx1xx5)/(100xx4)=Rs(375)/(2)=Rs187.50`
Withdrawing `Rs3000`, the principal becomes `=Rs(15000-3000)=Rs12000`
`:.` Then the simple interest of `Rs12000` in `3` months at the rate of `5%` per annum
`=Rs(12000xx5xx1)/(100xx4)=Rs150`
The rest time `=1` year - (`3` months `+3` months)
`=12` months `-6` months `=6` months.
`=(6)/(12)` year `=(1)/(2)` year
`:.` The principal of the last months `=Rs(12000+8000)=Rs20000`.
`:.` The simple interest of `Rs20000` in `6` months at the rate of `5%` per annum
`=Rs(20000xx5xx1)/(2xx100)=Rs500`
`:.` The toal interest `=Rs(500+150+187.50)=Rs837.50`
`:.` Total amount `=Rs(20000+837.50)=Rs20837.50`
`:.` Dipubabu will get an amount `Rs20837.50`.