Ross wants to buy a car worth 50 000 by financing it over a period of 36 months. The bank offers Ross an interest rate of 20% per annum, compounded monthly. They also offer him a 6 month grace period. (I.e. Ross does not have to pay anything until 6 months have passed, however, interest will still be charged during the grace period, from the beginning of the finance contract. Assume an ordinary annuity is in effect where necessary.) Calculate his monthly installment.