Question

30 cows eat 5 kg of grass in 20 days. How much grass is needed for 15 cows in 25 days.

Answer 1

As per the question,

30 cows eat 5 kg grass in 20 days
so 30 cows eat grass in 1 day = 5/20 = 1/4 kg.

So 15 cows will eat grass in 1 day= 1/4/2= 1/8kg.
So 15 cows wil eat grass in 25 days= 1/8 ×25.
=3.125kg

Answer 2

Hence 3.125 kg grass is needed for 15 cows in 25 days.

Step-by-step explanation:

Given:

30 cows eat 5 kg of grass in 20 days.

Grass eaten by 1 cow = $\frac{5}{30}$

                                     = $\frac{1}{6} kg$

Grass eaten by 1 cow per day = $\frac{\frac{1}{6} }{20}$

                                                  = $\frac{1 }{6 \times 20}$

                                                  =  $\frac{1 }{120} kg$

Now, grass eaten by 15 cows per day = $\frac{1 }{120} \times 15$

                                                                 = $\frac{1}{8} kg$

Therefore, grass eaten by 15 cows in 25 days = $\frac{1}{8} \times 25$

                                                                            = 3.125 kg

Hence 3.125 kg grass is needed for 15 cows in 25 days.