A gardener placed 4.5 kg of fresh grass clippings into a compost heap. After 30 days30\text{ days}30 days, the gardener reweighed the grass clippings and found that the mass had decreased to 3.6 kg. Calculate the rate of decomposition of the grass clippings in kg/day\text{kg/day}kg/day. Use the equation:
rate of decomposition=change in masstime taken \text{rate of decomposition} = \frac{\text{change in mass}}{\text{time taken}} rate of decomposition=time takenchange in mass