if the calculation is too time consuming,could you please just write down the formula and some hints .thanks!

8. 1000 is deposited in a fund A which earns an effective annual rate of 5%. At the end of each year, the interest earned plus an additional 50 are withdrawn and placed into a fund B which earns an effective annual rate of 9%. At the date when fund A is depleted, the accumulated value in fund B is used to buy a perpetuity which pays X every six months, the first payment issued 18 months after fund A is depleted the effective annual rate of the perpetuity account is 7%. Find X