backToThePast

function backToThePast(input) {

    let money = Number(input[0]);
    let lifeCycle = Number(input[1]);
    let age = 18;

    for (i = 1800; i <= lifeCycle; i++) {
        if (i % 2 === 0) {
            money = money - 12000;
            age++;
        } else {
            money = money - (12000 + 50 * age);
            age++;
        }
    }

    if (money >= 0) {
        console.log(`Yes! He will live a carefree life and will have ${money.toFixed(2)} dollars left.`);
    }
    else {
        console.log(`He will need ${Math.abs(money).toFixed(2)} dollars to survive.`);
    }
}
backToThePast([100000.15, 1808])