$(a)$ No, the two solutions do not have the same concentration.
$(b)$ The formula for mass percentage is:
$\text{Mass } \% = \frac{\text{Mass of solute}}{\text{Mass of solute} + \text{Mass of solvent}} \times 100$
For Ramesh's solution:
$\text{Mass of solute} = 10\,g$, $\text{Mass of solvent} = 100\,g$
$\text{Mass } \% = \left( \frac{10}{10 + 100} \right) \times 100 = \frac{10}{110} \times 100 \approx 9.09\%$
For Sarika's solution:
$\text{Mass of solute} = 10\,g$, $\text{Total mass of solution} = 100\,g$
$\text{Mass } \% = \left( \frac{10}{100} \right) \times 100 = 10\%$
Conclusion: The solution prepared by Sarika $(10\%)$ has a higher mass percentage than the solution prepared by Ramesh $(\approx 9.09\%)$.