There are total 200 students in a school, of which \( \frac{3}{10} \)th are boys. Find the number of girls in the school.
Simplify:
(7)² ÷ (7\( \frac{1}{2} \))⁴
A glass containing water has two holes. The 1st hole alone empties the glass in 9 minutes and 2nd hole alone empties the glass in 3 minutes. If water leaks out at a constant rate, how many minutes will it take if both the holes together empty the glass?
\( \frac{1}{4} \)
2 \( \frac{2}{4} \)
3 \( \frac{1}{4} \)
2 \( \frac{1}{4} \)