def GetCrProbs(rates, pixarea, exptime):
    """
    Calculate probabilities of CR hits.

    Parameters
    ----------
    rates: tuple of float
        CR hit rates (hits/cm^2/s).

    pixarea: float
        Pixel area (cm^2).

    exptime: float
        Exposure time (s).

    Returns
    -------
    probs: tuple of float
        Probabilities for respective elements in `rates`.
    """
    m = pixarea * exptime # cm^2 s
    probs = []
    for r in rates: probs.append( r * m) # hits
    return tuple(probs)