I Got Bills (6-9).js

var bills = [50.23, 19.12, 34.01,
    100.11, 12.15, 9.90, 29.11, 12.99,
    10.00, 99.22, 102.20, 100.10, 6.77, 2.22
];

var totals = bills.map(function(element) {
	element *= 1.15;
	element = element.toFixed(2);
	return Number(element);
});

console.log(totals);

tip

If you want convert string to number, use Number() method.