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PROBLEM SOLVING: A certain amount of money after a decade is said to be worth Php 10,000.00. If the interest rate after the first half of the projected period is 1.8% compounded weekly, and the next half has 2% compounded monthly, what must have been the principal amount in USD? Assume that there are 365 days in a year and 1 USD = 51 PHP at the end of the period, which increased 0.1 PHP after each year