(1) Every tenant shall pay rent and other charges payable within the time fixed by contract or in the absence of such stipulation, by the fifteenth day of the month next following the month for which it is payable and where any default occurs in the payment of rent or other charges, the tenant shall be liable to pay simple interest at the rate of fifteen per cent. per annum, from the date on which such payment of rent and other charges payable is due to the date on which it is paid.