Question

A dozen of articles cost 15. Find the cost of 100 such articles

Answer 1

1 dozen = 12

So, as per the question,

The cost of 12 articles is 15

∴ The cost of 1 article is (15/12)

                                      =(5/4)

∴ The cost of 100 articles = (5*100/4)

                                          = (5*25)

                                         = 125

So, the cost of 125 articles is 125.

It can also be done in proportional method.

So, let's do it in proportional method too_

Let the cost 100 articles be, 'x'

The cost of 12 articles is 15

∴ 12:15::100:x

Since, it is in direct proportion so,

12/15 = 100/x

⇒ 12x = 100*15

⇒ x = (100*15)/12

⇒ x = (25*15)/3

⇒ x = (25*5)

⇒ x = 125

So, the cost of 100 such articles is 125.