45%
47%
42 %
49%
Let the starting selling prices of \(A\) and \(B\) be \(p\).
Given that, she made profit of \(20\%\) on \(A\),
\(⇒ 1.2 \times c = p\)
\(⇒ c = \frac {5p}{6}\)
\(⇒\) cost of \(A = \frac {5p}{6}\)
Given that, she made a loss of 10% on \(B.\)
\(⇒0.9 \times c = p\)
\(⇒ c = \frac {10p}{9}\)
⇒ cost of \(B = \frac {10p}{9}\)
Now, she sold them at a price such that a \(10\%\) profit is made on \(B\).
Selling price \(= \frac {11}{10}\times \frac {10p}{9} = 9p \)
Now,
Profit % on \(A\),
\(=\frac {\frac {11}{9}-\frac {5}{6}}{\frac 56} \times 100\)
\(= 46.66\%\)
\(≃ 47\%\)
So, the correct option is (B): \(47\%\)