Ravindran borrowed $$15,000$ that is to be settled with

the following three installments: the first payment of

$$10,000$ in four months and two equal payments, one in

six months and the other in one year. Calculate the size

of each of the equal payments if the interest charged was

$4\mathrm{.}75\%$ p$.$a$.$ Let the focal date be one year from now.