Twelve wave crests move past a boat that is anchored at sea in a time of $180\,\text{s}$. The gap between neighbouring crests of the wave is $10\,\text{m}$. What is the speed of the wave?
- A$0.056\,\text{m s}^{-1}$
- B$0.67\,\text{m s}^{-1}$
- C$15\,\text{m s}^{-1}$
- D$18\,\text{m s}^{-1}$