Find the original numbers before the increase, then compute the overall percentage increase.<br><br>\\(\begin{aligned}<br>\text{Original boys} &= 121 \div 1.10 = 110<br>\\<br>\text{Original girls} &= 156 \div 1.04 = 150<br>\\<br>\text{Original total} &= 110 + 150 = 260<br>\\<br>\text{New total} &= 121 + 156 = 277<br>\\<br>\text{Increase} &= 277 - 260 = 17<br>\\<br>\text{Percentage increase} &= \frac{17}{260} \times 100\% = 6\frac{7}{13}\%<br>\end{aligned}\\)<br><br>Final Answer: \\(6\frac{7}{13}\%\\) (approximately 6.54%)