# Homework Help: Calculating the island of Manhattan gains after 400 years.

1. Jun 20, 2011

### lcam2

According to the legend, the island of Manhattan was purcased from the native indian population in 1626 for 24 dollars. Assuming this money was invested in a Dutch bank paying 5 %
simple interest per year, costruct a table in C++ showing how much money the native population would have at the end of each 50- year period, starting in 1626 and ending 400 years latter.
I'm having problems when i try to calculate the total amount of money every 50 year period.

2. Relevant equations

simple Interest = Principal amount * Interest rate * years

3. The attempt at a solution

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;
int main ()

{
float year;
double rate, interest, totMoney;

year = 1626;
rate = .05;

cout << " Year Interest gained Total Money" << endl;
cout << "-----------------------------------------------"<< endl;
cout << endl;

while( year <= 2026)
{

interest = 24 * .05* 50;
totMoney = 24 + interest;

cout << setw(7) << year << setw(15) << interest << setw(15)<< totMoney << endl;

cout << endl;

totMoney ++;

year += 50;

}

return 0;
}

2. Jun 21, 2011

### MATLABdude

The basic algorithm looks all right (I'd clean up the output format a little, but that's just me). However, is there a reason you're incrementing totMoney (totMoney++)? Does the legend include a $1 payment every 50 years? I'd also suggest using an int for year--you won't have any decimal artifacts in the year field. EDIT: And now compare it with compound interest--by 2026, that$24 would have turned into \$7,176,800,429.97.

Last edited: Jun 21, 2011