A person took a loan of $1000 to be paid in four payments. The first payment is due at the end of the 3rd month. The second payment is 2 times the first payment and is due at the end of the 6th month. The third payment is 3 times the first payment and is due at the end of the 9th month, and the final payment is due at the end of the 12th month, and is 4 times the first payment. Calculate the amount of payment that will be done using the simple interest rate of8%pa and the focal date of: a. 6th month b. 12th month