A student investigated the rate of decomposition of two different organic materials in a compost heap over a period of 60 days. Both heaps started with exactly 150 grams of material.
The results are shown in the table below:
| Time in days | Mass of grass clippings in grams | Mass of sycamore leaves in grams |
|---|---|---|
| 0 | 150 | 150 |
| 12 | 134 | 141 |
| 24 | 115 | 130 |
| 36 | 94 | 118 |
| 48 | 72 | 104 |
| 60 | 45 | 90 |
Calculate the rate of decomposition of sycamore leaves from 0 to 60 days. Give the unit.
