GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 35

Question

Which of the following strings are a member of the language described by the regular expression $\left(a^* {b} {a}^* b a^* b {a}^*\right)^*$

• A. $b b b b$
• B. $bbaaabb$
• C. $bbaaabbbabb$
• D. $b b a b b b a b$

Comments

im not able to derive Option C from given regex. For each exp number of b's possible is 3. suppose we assign "bbaaab" to first and "bbab" to second. Remains is 'b' . what am i missing? please help @Deepak Poonia

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I feel C should not be included in the answer as the language is accepting n(b)=3k..

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Answer will be only D.. @Lakshman Bhaiya

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Answer has been modified. Only D is correct.

Language of the given regular expression is set of all strings containing b's in multiple of 3.

Answer 1

C isn't possible here, sir. The strings should have b's which are multiples of 3.

Comments

Answer has been modified. Only D is correct.

Language of the given regular expression is set of all strings containing b's in multiple of 3.

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answer is D only.

Because numbers of b's should be in multiplies of 3.

Answer 2

( a^0 ba^0 ba^1 ba^0) ^2

=( b ba b) ^2

= bbabbbab

Answer : (D)

Answer 3

Answer is d as it will only have 3,6,9,12.......means 3n b