const calcTip = function(bill)
{
    return bill >= 50 && <= 300 ? bill*0.15: bill * 0.2;
    
}

const bills = [125, 555, 44];
const tips = [calcTip(bills[0]), calcTip(bills[1]), calcTip(bills[2])];

const total = bills+tips;
console.log(bills, tips);