01. Sum Seconds

function sumSeconds(input) {
    let firstTime = parseInt(input[0]);
    let secondTime = parseInt(input[1]);
    let thirdTime = parseInt(input[2]);
    let total = firstTime + secondTime + thirdTime;
    let minutes = Math.floor(total / 60);
    let seconds = total % 60;

    if (seconds < 10) {
        console.log(`${minutes}:0${seconds}`);
    } else {
        console.log(`${minutes}:${seconds}`);
    }
}

Taрикатско решение:)

function sumSeconds(input) {

    let total = parseInt(input[0]) + parseInt(input[1]) + parseInt(input[2]);

    console.log(`${Math.floor(total / 60)}:${total % 60 < 10? '0' : ''}${total % 60}`);

}