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Question
A farmer has enough food for 144 ducks for 28 days. If he sells 32 ducks how long will the food last?
Solution
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
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