Question

If $105kg$ corn is enough to feed 9 horses in a day, how much corn will be needed to feed 12 horses?

Answer 1

Hint:
Here, we will use the concept of unitary method to find the quantity of corn required to feed 1 horse in a day. Then we will multiply the quantity of corn required to feed 1 horse in a day by 12 to find the required number of corn needed to feed 12 horses.

Complete step by step solution:
According to the question,
Quantity of corn required to feed 9 horses in a day $ = 105{\text{kg}}$
Therefore, by unitary method, we can say that,
Quantity of corn required to feed 1 horse in a day $ = \dfrac{{105}}{9}{\text{kg}}$
Now, we are required to find the quantity of corn required to feed 1 horse in a day to feed 12 horses in a day.
Hence, multiplying both sides by 12, we get,
Quantity of corn required to feed 12 horses in a day $ = \dfrac{{105}}{9} \times 12$
Simplifying the expression, we get
$ \Rightarrow $ Quantity of corn required to feed 12 horses in a day $ = 35 \times 4 = 140{\text{kg}}$

Therefore, $140{\text{kg}}$ of corn is required to feed 12 horses in a day.
Thus, this is the required answer.

Note:
Here, we have used a unitary method to solve this question. Unitary method is a technique in which we find the value of a single unit (say 1kg corn) and then, we find the required value by just multiplying it on both the sides of this single unit. We might make a mistake that instead of multiplying 12 to the quantity required to feed 1 horse, we might divide it by 12, which will give us the wrong answer.