Hours.Decimal Hours

[Joe Horn]

Here's one way of doing it on the HP-15C which is not the most efficient but is easily understood:

Type 0.0001 (that's one second in HP's HMS format)
→H (to convert to decimal hours)
100 × (to multiply by 100)
→HMS (converts the result to 0.0140, that is, 0 hours, 1 minute, 40 seconds)