Question

A farmer has enough food to feed 20 animals in his cattle for 8 days how long would the food last if there were 10 more animals in his cattle?

Answer 1

animals

20 no of days

20+10 = 30 8days

20*x =30*8

240/20=12

the food last for 12 days

Answer 2

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,

$x_1 = 20, \: y_1 = 8, \: x_2 = 30$ and $y_2 = p$ (let)

=> 20 × 8 = 30 × p

=> 160 = 30p

=> p = 160/30

=> p = 5.33

Hence the required number of days = 5.33