def IRADCTaxCredit(e03150, e03300, IRADC_credit_c, IRADC_credit_rt, iradctc):
    """
    Computes refundable retirement savings tax credit amount.
    """
    # calculate refundable credit amount 
    tot_retirement_contributions = e03150 + e03300
    if IRADC_credit_rt > 0.:
        iradctc = min(tot_retirement_contributions * IRADC_credit_rt, IRADC_credit_c)
    else:
        iradctc = 0.
    return (iradctc)