Priya deposited a certain amount in Savings Scheme X, which offered a simple interest rate of 12.5% p.a. for 4 years. After 4 years, the total amount she received was ₹18,000. If the same amount was instead invested in Investment Plan Y, which offered a compound interest rate of 20% p.a. for 3 years (compounded annually), how much interest would she have earned from Plan Y after 3 years?