hi

I've got two questions and was wondering if you could help:

1. if a deep water wave has a period of 18 seconds, what is its speed of travel?

I no that speed= wavelength/ period but how do you go about doing it without knowing the wavelength?

2. for a wave of wavelength 280 m, what is its speed of travel?
this is also similar how would you go about doing it without knowing the period?

thank you

According to this site:
Ocean surface wave - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Ocean_surface_wave)

for deep water waves the speed and wavelength are related by:

speed = 1.25 sqrt \lambda

where \lambda is in meters and speed is in m/s.

Perhaps this relationship is described in your text book? With this you should be able to solve the problems.