Let the required number of days be x.
| Number of days | 28 | x |
| Number of ducks | 144 | 144 32 = 112 |
As the number of ducks decreases the food will last for more days.
They are in inverse proportion.
x1y1= x2y2
28 144 = x 112
x = $(28 xx 144)/112$
x = 36
The food lasts for 36 days
