Android Java - withdraw money output?

In my Java Program I have a method:

private void giveCash(int money) {
    int banknotes[] = {10, 20, 50, 100, 200, 500};
    StringBuffer cash = new StringBuffer();
    int i = banknotes.length - 1;
    while (i >= 0)
        if (banknotes[i] > money)
            i--;
        else {
            cash.append(banknotes[i]).append(" ");
            money -= banknotes[i];
        }
    // display cash in cash field
    TextView cash = (TextView) findViewById(R.id.cash);
    cash.setText(cash);
}

For, example, if money == 990 the output will be: 500 200 200 50 20 20

How to do the output: 500x1, 200x2, 50x1, 20x2 ?