Mr Dasson invested certain amount in three different schemes “Slow”, “Medium” and “Fast” with the rate of interest 10% p.a., 12% p.a. and 15% p.a. respectively. If the total interest accrued in one year was Rs. 32,000 and the amount invested in Scheme “Fast” was 150% of the amount invested in Scheme “Slow” and 240% of the amount invested in Scheme “Medium” , what was the amount invested in Scheme “Medium”?