A R$250000$ loan is to be amortized by equal

monthly payments of R$6112\mathrm{.}77$ over $5$ years. The

loan is secured at $16\mathrm{.}25\%$ p$.$a$.($cm$).$ The payments

from T$40$ to T$44$ are missed. At T$45$ the interest

rate changes to $14\%$ p$.$a$.$ effective. Determine

a$)$ the additional payment that must be added to the $45$th payment to compensate for the missed payments.