Question

Question number 19 of RD Sharma

Answer 1

We know that 1 score = 20.

We know that 1 dozen = 12.

(i)

Given that pencil cost 16 per score.

So, Cost of 20 pencils = 16.

Then the cost of 1 pencil = 16/20 = 0.8.

(ii)

Given that ball pen cost 8.40 per dozen.

So, Cost of 12 ball pens = 8.40.

Then the cost of 1 ball pen = 8.40/12 = 0.7.

Now,

Ratio of price of 1 pencil to that of 1 ball pen :

⇒ 0.8 : 0.7

⇒ 8 : 7.

Hope it helps!

Answer 2

Solution

Given : Rate of pencil is ₹16 per score
Rate of pens is 8.40 per dozen

To Find : Ratio of the prices

Solution :

Score is used for 20 items

1 Score = 20 pencils

Dozen is used for 12 items

1 Dozen = 20 ball pens

Now ,

Rate of one pencil = x

20 pencil = ₹ 16

$\bold{x \: = \: \dfrac{16}{20}}$

$\bold{x \: = \: \dfrac{8}{10}}$

$\bold{x \: = \: Rs\: 0.8}$

Rate of one ball pen

12 ball pens = ₹ 8.40

$\bold{x \: = \: \dfrac{8.4}{12}}$

$\bold{x \: = \: \dfrac{84}{120}}$

$\bold{x \: = \: \dfrac{7}{10}}$

$\bold{x \: = \: Rs\: 0.7 }$

Ratio of pencil and ball pen = $\bold{\dfrac{0.8}{0.7}}$

Answer

$\bold{\boxed{\boxed{Ratio\: = \: \dfrac{8}{7} \: or \: 8\colon7}}}$