Consider this

function Pair(inMin, inMax)
{
    this.min = inMin;
    this.max = inMax;
}

Which would let me use

var somepair = new Pair(5,10);
somepair.min => 5
somepair.max => 10

See this function now

function getTotalScaledScorePair()
{
    var rpair = getReadingScaledScorePair();
    var wpair = getWritingScaledScorePair();
    var mpair = getMathScaledScorePair();
    
    var tmin = rpair.min + wpair.min + mpair.min;
    var tmax = rpair.max + wpair.max + mpair.max;
    return new Pair(tmin, tmax);
}