Ricky Ricky - 1 year ago 58
Javascript Question

Percentage from number input and add that to new total value

I am trying to add the given percentage onto a number that already has that percentage added on.

I.e, The user defines 25% (this is not set could be any number percentage) I then add 25% onto the amount they invested to start with so for example:

Customer invests £10,000, I add 25% onto £10,000, which equals £12,500. AND THEN the following month I add the 25% onto the £12,500 from the month before, which should equal £15,625.

Yet for all my overthinking i believe i have over complicated things in my head. It should be a case of simple maths, yet i cannot figure this out in Javascript.
I keep getting the value of £15,000, and cannot work out how to store the given percentage in a variable itself and then add that percentage onto the Total amount.

I really have spent far too long overthinking this and suppose it is really simple, but i have hit a wall now.Please only answer in Javascript, Not Jquery.

Here is some code.

// Set the values...
Num = prompt("Enter a percentage using a decimal Number...");
interestRate = Num*100;
startCash = 10000;
total = startCash*interestRate/100+startCash;
month = 1;

// Inputting Text...
StartText = "Starting Money: £";
IntText = "Interest Earned: ";
TotalText = "Total Amount: £";
MonthText = "Month: ";

displayStart = StartText + startCash + "\n";
dispInt = IntText + interestRate + "\n";
dispTotal = TotalText + total + "\n";
dispMonth = MonthText + month + "\n";

dispvalue = displayStart + dispInt + dispTotal + dispMonth;

console.log (dispvalue);

addInt = total + interestRate*100;

console.log (addInt);

Answer Source

The total from compound interest calculated for the next month should be

addInt = total*interestRate/100 + total;

just like the fifth line of your code.

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