The cost of one pencil is Rs. 1.50, then the cost of 10 pencils is-
A. Rs 15
B. Rs. 150
C. Rs. 1.5
D. None of these
Last updated date: 26th Mar 2023
•
Total views: 305.7k
•
Views today: 7.82k
Answer
305.7k+ views
Hint: For this type of question unitary method is required and we must also know the multiplication involving decimal.Cost of one pencil is given, we have to find the cost of 10 pencils ,So multiply cost of one pencil with number of pencils to get the required answer.
“Complete step-by-step answer:”
Unitary method says that if the cost of x item is Rs. y then cost of 1 item is $\dfrac{y}{x}$ …(i) . Now if we wish to calculate cost of z items then it will be $z\times \dfrac{x}{y}$ …(ii)
Now we will use this principle in our question to calculate the cost of 10 pencils.
In the question we are already given the cost of 1 pencil so we don’t need to use equation (i) . Now we will use equation (ii) to calculate the cost of 10 pencils.
Therefore, our $\dfrac{x}{y}=Rs.\,1.50$ and z is equal to 10
Therefore, cost of 10 pencils is given by-
$\dfrac{x}{y}\times z=1.50\times 10$
Now, we need to multiply 1.50 by 10 which is done just like normal multiplication; only the decimal is put before the number of digits that were after the decimal in the numbers which are being multiplied.
Therefore, $1.50\times 10=15.0$
In this multiplication we can see that when we do $150\times 10$ , we get 1500 and then we put decimal before the last two digits because in 1.50 we have two digits after decimal.
Hence, the answer is Rs. 15.0 .
Note: We must know that if after decimal there is 0 it has no value, it means 15.0=15 and if 0 occurs at last in a number having decimal then again it has no value. Therefore, 1.50=1.5
“Complete step-by-step answer:”
Unitary method says that if the cost of x item is Rs. y then cost of 1 item is $\dfrac{y}{x}$ …(i) . Now if we wish to calculate cost of z items then it will be $z\times \dfrac{x}{y}$ …(ii)
Now we will use this principle in our question to calculate the cost of 10 pencils.
In the question we are already given the cost of 1 pencil so we don’t need to use equation (i) . Now we will use equation (ii) to calculate the cost of 10 pencils.
Therefore, our $\dfrac{x}{y}=Rs.\,1.50$ and z is equal to 10
Therefore, cost of 10 pencils is given by-
$\dfrac{x}{y}\times z=1.50\times 10$
Now, we need to multiply 1.50 by 10 which is done just like normal multiplication; only the decimal is put before the number of digits that were after the decimal in the numbers which are being multiplied.
Therefore, $1.50\times 10=15.0$
In this multiplication we can see that when we do $150\times 10$ , we get 1500 and then we put decimal before the last two digits because in 1.50 we have two digits after decimal.
Hence, the answer is Rs. 15.0 .
Note: We must know that if after decimal there is 0 it has no value, it means 15.0=15 and if 0 occurs at last in a number having decimal then again it has no value. Therefore, 1.50=1.5
Recently Updated Pages
Paulings electronegativity values for elements are class 11 chemistry CBSE

For a particle executing simple harmonic motion the class 11 physics CBSE

Does Nichrome have high resistance class 12 physics CBSE

The function f satisfies the functional equation 3fleft class 12 maths JEE_Main

Write a letter to the Principal of your school to plead class 10 english CBSE

Look at the handout below Write a letter to the organizers class 11 english CBSE

Trending doubts
What was the capital of Kanishka A Mathura B Purushapura class 7 social studies CBSE

Difference Between Plant Cell and Animal Cell

Write an application to the principal requesting five class 10 english CBSE

Ray optics is valid when characteristic dimensions class 12 physics CBSE

Give 10 examples for herbs , shrubs , climbers , creepers

Tropic of Cancer passes through how many states? Name them.

Write the 6 fundamental rights of India and explain in detail

Write a letter to the principal requesting him to grant class 10 english CBSE

Name the Largest and the Smallest Cell in the Human Body ?
