Question

I = prt

I = simple interest, p = principal, r = rate, t = time.
You want to study at the Hogwarts School of Witchcraft and Wizardry after five years. You need 800 pieces of muggle-money to study there. You decide to deposit some pieces in the bank at an annual interest rate of %12.

Answer 1

The amount we need to invest is 500 muggle money.

Explanation:

Amount needle to study at Hogwarts = A = 800 muggle money

Principle amount that we need to invest = P

Duration of investment = T = 5 years

Rate if simple interest = R = 12%

Simple interest = S.I

A = S.I + P

`800=(P* 12* 5)/(100)+P`

`800=0.6P+P`

`800=1.6P`

P =
`(800)/(1.6)=500`

The amount we need to invest is 500 muggle money.