Question

A farmer has enough food to feed 28 animals in his cattle for 9 days. how long would the food last, if there were 8 more animals in his cattle

Answer 1

animals=28
days=9
animals added=8
total animals =36
food will last for =36×9/28
=9×9/7=81/7
=11.57 days

Answer 2

Answer:

7 days

Step-By-Step Explanation:

If the number of animals increases, then it will take fewer days to last.

Then the two quantities are in inverse proportions.

Let the required number of days be p.

$\because x_1y_1 = x_2y_2$

Where,

$x_1 = 28, \: y_1 = 9, \: x_2 = 36$ and $y_2 = p$ (let)

=> 28 × 9 = 36 × p

=> p = 28 × 9/36

=> p = 7

Hence the required number of days = 7.