Suppose you are $40$ years old and plan to retire in exactly $20$ years. $21$ years from now you will need to withdraw RM$5,000$ every six month from a retirement fund to supplement your daily life expenses. You expect to live to the age of $85.$ How much money should you place in the retirement fund every six month for the next $20$ years to reach your retirement goal if you can eam $12\%$ interest per year from the fund?

$[5$ marks$]$