Question

A pencil costs ₹
$1 \ \frac{1}{2}$
and a pencil box containing 10 pencils costs ₹13. How much money do you have to pay extra, if you buy 10 pencils individually rather than the entire box?​

Answer 1

Cost of 1 pencil =

$1 \times \frac{1}{2} = \frac{3}{2}$

Cost of ten pencils =

$\frac{3}{2} \times \frac{10}{1} = 15$

Extra money to be paid =

15-13= 2 rupees

Answer 2

Given - Cost of pencil and pencil box

Find - Difference in cost

Solution - Converting the cost of 1 pencil in improper fraction.

The cost of 1 pencil = $1 \times \frac{1}{2}$

The cost of 1 pencil = $\frac{3}{2}$

Cost of 10 pencils = $\frac{3}{2} \times 10$

Performing division

Cost of 10 pencils = $3 \times 5$

Performing multiplication

Cost of 10 pencils = Rupees 15

Difference in cost of 10 pencils and 1 pencil box = 15 - 13

Performing substraction

Difference = 2

Hence, Rupees 2 will be paid extra on buying 10 pencils individually rather than the entire box.