The total surface area of a solid hemisphere is 42 cm². Its radius (in cm) is:
(Take π =\( \frac{22}{7} \))
\(\frac{7}{\sqrt{11}}\)
\(\frac{7\sqrt{2}}{\sqrt{22}}\)
\(\frac{7\sqrt{3}}{\sqrt{11}}\)
\(\frac{7}{\sqrt{22}}\)
A man walking at a speed of 10 km/h crosses a bridge in 7\( \frac{1}{2} \) minutes. The length of the bridge is ____ metres.
All 30 students are standing in a straight line facing the north. Amit is at 12th position from the extreme left end. What is the position of Amit when considered from the extreme right end?