mathematics of finance question. urgent answer thnx :)?

[Te P]

13. A person has $4600 in an account which is earning interest at j2 = 5.1%. What level deposit is required at the end of each half-year for the next 4 years if the account balance is to be $9900 at the end of the 4 years?
(The deposits will be $4600 at time 0 and $R at times 1 to (2×4) inclusive. With focal date at time (2×4) the accumulation of these deposits will equal $9900. Don't forget to give interest to the single payment of $4600.)