A is sentenced to a fine of five hundred rupees and to four months' imprisonment in default of payment. He has completed 50 days of imprisonment and then paid four hundred  rupees. When should he be discharged?

Section 69 IPC- Termination of imprisonment on payment of proportional part of fine.—If, before the expiration of the term of imprisonment fixed in default of payment, such a proportion of the fine be paid or levied that the term of imprisonment suffered in default of payment is not less than proportional to the part of the fine still unpaid, the imprisonment shall terminate. Illustration A is sentenced to a fine of one hundred rupees and to four months' imprisonment in default of payment. Here, if seventy-five rupees of the fine be paid or levied before the expiration of one month of the imprisonment, A will be discharged as soon as the first month has expired. If seventy-five rupees be paid or levied at the time of the expiration of the first month, or at any later time while A continues in imprisonment, A will be immediately discharged. If fifty rupees of the fine be paid or levied before the expiration of two months of the imprisonment. A will be discharged as soon as the two months are completed. If fifty rupees be paid or levied at the time of the expiration of those two months, or at any later time while A continues in imprisonment, A will be immediately discharged.