Question

You want to study at the Hogwarts School of Witchcraft and Wizardry after three years. You need 910910 pieces of muggle-money to study there. You decide to deposit some pieces in the bank at an annual interest rate of 10\%10%.

How many pieces should you deposit today if you want to use the total amount to pay the fees?

Answer 1

You should deposit 700 pieces today if you want to use the total amount to pay the fees.

Explanation:

Answer 2

You should deposit 700 pieces today if you want to use the total amount to pay the fees.

Explanation:

Suppose, you should deposit
`P` number of pieces today.

Formula for simple interest:
`I= P*r*t` , where I = Amount of interest, P= Initial deposit amount, r= rate of interest in decimal form and t= time duration.

Here, the
`P` number of pieces is deposited at an annual interest rate of 10% for three years. That means,
`r= 10\%= 0.10` and
`t= 3`

Using the above formula, we will get.......

`I= P*0.10*3 = 0.3P`

Given that, you need total 910 pieces of muggle-money to study after three years. So, the equation will be......

`P+I= 910\\ \\ P+0.3P=910\\ \\ 1.3P=910\\ \\ P=(910)/(1.3)=700`

So, you should deposit 700 pieces today if you want to use the total amount to pay the fees.