TIFR CSE 2010 | Part A | Question: 9

Question

A table contains $287$ entries. When any one of the entries is requested, it is encoded into a binary string and transmitted. The number of bits required is.

• A. $8$
• B. $9$
• C. $10$
• D. Cannot be determined from the given information.
• E. None of the above.

Answer 1

$D$ should be the correct answer.

Each Entry represents a row of table,in general.

In order to encode all the information of a row/entry, we must know what is the size of that information.But it is not mentioned in the question.

We can ADDRESS 287 entries by ceiling of $\log 2$(287) = $9$ bits.

but we CAN NOT ENCODE an entry, without knowing the size of that entry

So I don't think it is possible to tell how many bits are required to encode & transmit an entry unless any information is given about the data contained in entries.

Comments

i would approach this way let's table size (m x n)

m*n =287  

if we can m=n and asking for no of bits   2^m*n =287  nothing can be decide

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@Prateek kumar

In table size is m*n what do m and n stand for? m= no. of entries and n is the size of each entry?

Then m=287. How can you say m*n=287? 

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Let among 287 entries some are 12,1023,13002. Then 12 can be encoded using 4 bits, 1023 needs 10 bits and 13002 needs 14 bits. So we need to know the size of each entry or atleast the max entry to encode. Knowing how many entries won't help here. 

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why "it" in the question cannot refer to the "request"?

What's wrong with the following interpretation of the question -

1. A table contains $287$ entries;

2. When any one of the entries is requested, it (the request) is encoded into the binary string and (the encoded string) is transmitted.

3. The number of bits required (to transmit such request) is ___

--> $9$ bits