def ar_to_vaf(ar):
    """
    Convert AR to VAF.

    VAF (variant allele frequency) = V-AF
    AR (allele ratio) = V-AF / WT-AF
    V-AF + WT-AF = 100 (%)

    Args:
        ar (float): AR to convert.

    Returns:
        VAF (float)

    """
    return ar/(ar + 1) * 100