Question

You want to study at the Hogwarts School of Witchcraft and Wizardry after three years. You need 910 pieces of muggle-money to study there.

You decide to deposit some pieces in the bank at an annual interest rate of 10% percent.

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

Answer 1

Answer:

so we need to find the principal amount here,

time period = 3 years

interest = 10%

final amount = 910

n = number of times interest applied per time period = 1

p = ?

Step-by-step explanation:

consider your currency as dollar for easy reference

this solution is for compound interest:

First, convert R percent to r a decimal

r = R/100

r = 10%/100

r = 0.1 per year,

Then, solve our equation for P

P = A / (1 + r/n)nt

P = 910.00 / (1 + 0.1/1)(1)(3)

P = $ 683.70

Summary:

The principal investment required to get

a total amount of $ 910.00

from compound interest at a rate of 10% per year

compounded 1 time per year

over 3 years

is $ 683.70.

simple interest solution:

First, converting R percent to r a decimal

r = R/100 = 10%/100 = 0.1 per year.

Solving our equation:

P = 910 / ( 1 + (0.1 × 3)) = 700

P = $700.00

The principal investment required to get a total amount, principal plus interest, of $910.00 from simple interest at a rate of 10% per year for 3 years is $700.00.

there you have your answer,

please mark me as brainliest

thank you

Answer 2

Answer:

700 pieces

Step-by-step explanation:

We can think of the number of pieces we must deposit today as the principal. Then, we need to find what this principal must be if we want the principal plus the three-year interest to be 910.

Let's first find the three-year interest.

We know that the annual interest rate =10%.

This means the interest in 1year =10% of the principal.

Then, the interest in 3years =(3×10)% of the principal.

Three-year interest =30% of the principal.

We want the principal and the three-year interest to add up to 910 Let's call the principal with the nick-name P.

P+ 30% of P = 910

100%+ 30%of P=910

We can think of P as 100% of P. This is the same as multiplying and dividing P by 100

Now, let's calculate the principal.

130% of P=910

130/100 X P = 910

P=910 X 100/130

P= 700

whew that was long, hope this helps!