Grandpa Stavri

function grandpaStavri(input) {
    let days = Number(input[0]);
    let totalLiters = 0;
    let averageGradus = 0;

    for (let i = 1; i <= days * 2; i++) {
        let liters = Number(input[i++]);
        let gradus = Number(input[i]);
        totalLiters += liters;
        averageGradus += liters * gradus;
    }

    console.log(`Liter: ${totalLiters.toFixed(2)}`);
    console.log(`Degrees: ${(averageGradus / totalLiters).toFixed(2)}`);
    if (averageGradus < 38) {
        console.log("Not good, you should baking!");
    } else if (averageGradus <= 42) {
        console.log("Super!");
    } else {
        console.log("Dilution with distilled water!");
    }
}

РЕШЕНИЕ СЪС SHIFT() И ТЕРНАРЕН ОПЕРАТОР:

function grandpaStavri(input) {
    let days = Number(input.shift());
    let totalLiters = 0;
    let averageGradus = 0;

    for(let i = 0; i < days; i++) {
        let liters = Number(input.shift());
        let gradus = Number(input.shift());
        totalLiters += liters;
        averageGradus += liters * gradus;
    }

    console.log(`Liter: ${totalLiters.toFixed(2)}`);
    console.log(`Degrees: ${(averageGradus / totalLiters).toFixed(2)}`);
    console.log( averageGradus < 38? "Not good, you should baking!" : averageGradus <= 42 ? "Super!" : "Dilution with distilled water!");
}