Question

The cost of 12 notebooks is 228. Find the cost of 1 notebook.

Answer 1

Hint: Use the unitary method to solve this type of question. In this question, divide the total cost of all the notebooks by the total number of notebooks to get the cost of one notebook.

Complete step-by-step answer:

We are given that the cost of 12 notebooks is Rs. 228. We have to find the cost of 1 notebook. Before proceeding with this question, we must know what the unitary method is. The word unitary refers to a single or an individual unit. Hence, this method aims at determining the values in relation to a single unit. For example, if a man eats 25 mangoes in 5 hours then we can use the unitary method to find out the mangoes he will eat in 1 hour. We can also say that the unitary method is a technique for solving a problem by first finding the value of a single unit and then finding the necessary value by multiplying the single unit value. In essence, this method is used to find the value of a unit from the value of a multiple and the value of a multiple.

Now let us consider the information given in the question. We are given that the cost of 12 notebooks = Rs. 228. So, to get the cost of 1 notebook, we will divide the total cost of the given notebooks by the total number of notebooks. So, we get,
The cost of one notebook \[=\dfrac{\text{Total cost of notebooks}}{\text{Total number of notebooks}}\]

By substituting the total cost of notebooks = Rs. 228 and the total number of notebooks = 12 in the above equation, we get,
Cost of one notebook \[=\dfrac{228}{12}=Rs.19\]
So, we get the cost of one notebook as Rs. 19.

Note: Students must learn properly how to use the unitary method as this method finds its extensive use not only in theory but practically as well ranging from distance, time problems to the problems related to calculating the cost of our day to day requirements. Also, some students make this mistake of dividing 12 by 228 instead of 228 by 12 to calculate the cost of one notebook. So these mistakes should be taken care of.