var originalArr = [40, 20, 30, 10, 50];
var someArr = [ 10, 3, 30, -10, 24.6, 33.5, 0, 5, 7, -99, -33, 5, 60, 11.6, -42.8];
var a = [1, 4, 100];

var combineArr = function () {
    var newArr = [],
    length = arguments.length;

    for(var i = 0; i < length; i++) {
        newArr = newArr.concat(arguments[i]);
    }
    return newArr;
};

console.log(combineArr(originalArr, someArr, a))