The correct answer is (B): \(399\)
Let the total marks be \(T\) and scores of Bishnu, Asha and Ramesh be \(a\), \(b\) and \(c\) respectively.
Given, \(a\) = \(52\%\) of \(T\) = \(c-23\) and \(b= 64\%\) of \(T\) = \(c+34\)
Hence, \((64-52)\%\) of \(T\)=\((c+34)-(c-23)\) = \(57\)
i.e. \(12\%\) of \(T\) = \(57\)
Hence, score of Geeta = \(84\%\) of \(T\) = \(7×57=399\)
Let total marks be \(100x\).
Marks obtained by Bishnu \(=52x\)
Marks obtained by Asha \(= Mx\)
Marks obtained by Ramesh \(= 52x+23\)
Marks obtained by Ramesh \(= 64x-34\)
\(⇒ 52x+23 = 64x-34\)
\(⇒ 64x-52x = 34+23\)
\(⇒ 12x = 57\)
\(⇒ x = \frac {57}{12}\)
\(⇒ x = \frac {19}{4}\)
Marks obtained by Geeta \(=84x\)
\(= 84 \times \frac {19}{4}\)
\(=21 \times 19\)
\(=399 \)
So, the correct option is (B): \(399\)