A special production turbo-engined vehicle is offered at quite a high price which is Rp. 400,000,000 and can be purchased by paying a DP of 20% and the rest with Bank Artos credit with interest of j12 = 15% repaid in 30 months. Without creating a table amortization, calculate: a. The amount of installments per month b. The amount of the credit balance after the 15th installment payment c. The amount of principal paid for the first 20 months d. The amount of interest paid during the last 10 months e. The amount of monthly installments if at the end of the third month, the interest rate is increased to 16.2% p.a