Question

5. 4 erasers are purchased for rs.10. Find the cost of on dozen erasers.

Answer 1

Question

5. 4 erasers are purchased for rs.10. Find the cost of on dozen erasers.

ANSWER :

Cost of 4 erasers = Rs.10

Cost of 1 eraser = $\frac{10}{4}$ = Rs. 2.5

Now,

To be found :-

The cost of one dozen erasers

= 2.5 × 12        [ $\therefore$ as 1 dozen = 12 ]

= Rs.30

Hence,  

The cost of one dozen erasers is Rs.30

Answer 2

$<b>$
Given,
4 Erasers cost Rs 10
1 Dozen Erasers cost ? Rs

1 Dozen = 12 (in number)

4 Erasers --- 10 Rs
12 Erasers --- ? Rs (Say x)

By using Cross Multiplication
4 × x = 10 × 12
4x = 120
$\implies x = \frac{120}{4}$
$\implies x = 30$


Therefore,
Cost of one Dozen of Erasers = 30 Rs