Annie invested a certain sum of money in a bank that paid simple interest. The amount grew to Tk. 240 at the end of 2 years. She waited for another 3 years and got a final amount of Tk. What was the principal amount that she invested at the beginning?
সমাধান
সঠিক উত্তর: Option A
The sum grew to 240 at the end of 2 years.
At the end of another 3 years, the sum grew to 300.
i.e. in 3 years, the sum grew by 60.
Therefore, each year, it grew by 20.
Sum at the end of 2 years = 240
Sum grew by 20 each year.
Hence, in the first 2 years, sum grew by 2 * 20 = 40.
Therefore, sum at the beginning of the period = Sum at the end of 2 years - 40 = 240 - 40 = 200.
