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Answer the questions on the basis of the information given below.

Purana and Naya are two brands of kitchen mixer-grinders available in the local market. Purana is an old brand that was introduced in $1990$, while Naya was introduced in $1997$. For both these brands, $20\%$ of the mixer-grinders bought in a particular year are disposed off as junk exactly two years later. It is known that $10$ Purana mixer-grinders were disposed off in $1997$. The following figures show the number of Purana and Naya mixer-grinders in operation from $1995$ to $2000$, as at the end of the year.

How many Naya mixer-grinders were disposed off by the end of $2000$?

1. $10$
2. $16$
3. $22$
4. Cannot be determined from the data

Question has asked for “Number of Naya mixer grinders disposed off by the end of $2000$” or cumulative sum of all the disposed Naya products by the end of $2000$. It is also known that $20\%$ of the product bought is disposed off $2$ years later.

As Naya mixer grinders were introduced in $1997$, so first disposal should be in the year $1999$ and second disposal in $2000.$

In $1999:- 20\%$ of products bought in $1997$ is disposed or $20\%$ of $30 =6 \text{(D1)}$

In $2000:- 20\%$ of the new products bought in $1998$ is disposed, or $20\%$ of $(80-30)=10 \text{(D2)}$

Total disposal $= \text{D1+D2}=16$

Option $: \text{B}$
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