Question

There is enough grass to feed 5 cows for 8 days.
How long would the same amount of grass feed 8 cows?

Answer 1

Answer:

5 days

Step-by-step explanation:

This is a case of inverse proportion.

therefore,

5 cows => 8 days                     8*5=40

8 cows = 40/8 (days) = 5 days

Answer 2

Given: 5 cows can feed on the grass for 8 days.

To Find: How many days can 8 cows feed on the same amount of grass?

Solution:

Number of days in which 5 cows can eat= 8 days

∵ Number of days in which 1 cow can eat= 8 $\times$ 5 days

∴ Number of days in which 8 cows can eat= $\frac{8 \times 5}{8}$ days

                                                                   = 5 days

Answer: 8 cows can feed on the same amount of grass for 5 days.

Note

• When the number of cows drops down to 1, the food will last for more number of days. Therefore, the number of days is multiplied.

• When the number of cows rises to 8, the food will last for less number of days. Thus, the number of days is divided.