A person named 'P' invested Rs. 48,000 in an SIP called 'X', which provides compound interest at a rate of 50% per annum, compounded half-yearly, for a duration of 12 months. Afterward, he reinvested the interest earned from SIP 'X' into another SIP, 'Y', which offers compound interest at an annual rate of 'a%', compounded annually, for 3 years. By following this investment strategy, he accumulated a total interest of Rs. 46,656 over 4 years. The expression (1.3a - 2) represents the root of which of the following equations?

• I b² - 41b + 378 = 0 I
• I b² - 51b + 518 = 0 II
• I b² - 61b + 888 = 0 I
• V b² - 71b + 1258 = 0