Deposit Profit

You have deposited a specific amount of money into your bank account. Each year your balance increases at the same growth rate. With the assumption that you don't make any additional deposits, find out how long it would take for your balance to pass a specific threshold.

Example

For deposit = 100, rate = 20, and threshold = 170, the output should be

deposit_profit(deposit, rate, threshold) = 3`

Each year the amount of money in your account increases by 20%. So throughout the years, your balance would be:

• year 0: 100;
• year 1: 120;
• year 2: 144;
• year 3: 172.8.

Thus, it will take 3 years for your balance to pass the threshold, so the answer is 3.

Solution

PYTHON

def deposit_profit(deposit, rate, threshold):
    years = 0
    money = deposit
    while money < threshold:
        years += 1
        money += money * rate / 100
    return years


print(deposit_profit(100, 20, 170))

JAVASCRIPT

function depositProfit(deposit, rate, threshold) {
  let years = 0;
  let current = deposit;
  while (current < threshold) {
    current += (current * rate) / 100;
    years++;
  }
  return years;
}

console.log(depositProfit(100, 20, 170));