During a 3-year period when his business was prospering, Jack was able to deposit $1,000 at the end of each month in an account earning 12 percent compounded monthly. The business slackened, and jack...

During a
3-year period
when his business was prospering, Jack was able to
deposit $1,000
at the end of each month in  an  account
earning  12  percent  compounded  monthly.   The  business  slackened,  and  jack  could  not  continue the deposits.  Moreover, the interest rate on his accumulated deposits fell to
8 percent compounded quarterly
and remained at
this level for 10 years, at which time Jack decided to exhaust the account by withdrawing equal amounts at the end of
every 6 months for 5 years.  The
interest rate remained at 8 percent compounded
semiannually over the time of the withdrawals.
How much did Jack withdraw every 6 months ?

solving these math details