How do I add minutes so they turn into hours? - addition

Question

This may be a simple question but how do I add minutes so they will turn into hours i.e. if you add 30 minutes and 30 minutes and 30 minutes it will give an answer of 1 hour and 30 minutes?
So far I just have the minutes totalling:
function findTotalHours(){
var arr = document.getElementsByName('hours');
var tot=0;
for(var i=0;i<arr.length;i++){
if(parseInt(arr[i].value))
tot += parseInt(arr[i].value);
}
document.getElementById('totalHoursv').value = tot;
}
function findTotalMins(){
var arr = document.getElementsByName('minutes');
var tot=0;
for(var i=0;i<arr.length;i++){
if(parseInt(arr[i].value))
tot += parseInt(arr[i].value);
}
document.getElementById('totalMins').value = tot;
}
I have created a js fiddle to show the table which isn't working correctly...ie it is giving 90 minutes as answer
https://jsfiddle.net/Vicky1984/kLurp45y/9/
Any advice greatly appreciated, I'm totally new to javascript
thanks

Answer 1

function findTotalHours(){
var arr = document.getElementsByName('hours');
var tot=0;
for(var i=0;i<arr.length;i++){
if(parseInt(arr[i].value))
tot += parseInt(arr[i].value);
}
return tot;
}
function findTotalMins(){
var arr = document.getElementsByName('minutes');
var tot=0;
for(var i=0;i<arr.length;i++){
if(parseInt(arr[i].value))
tot += parseInt(arr[i].value);
}
return tot;
}
function calculateAllocation(){
var mins = findTotalMins();
var hrs = findTotalHours();
hrs = hrs + (mins-mins%60)/60;
mins = mins%60;
document.getElementById('totalHoursv').value = hrs;
document.getElementById('totalMins').value = mins;
}
In onblur event call calculateAllocation() for both hours and minute input field
Demo:
https://jsfiddle.net/kLurp45y/19/