Answer:
2.43 m
Step-by-step explanation:
From the question given above, the following data were obtained:
Number of wave crest = 7
Time = 10 s
Distance between each crest = 2.43 m
Wavelength =? 
The wavelength of a wave is simply defined as the distance between two crest or trough of a wave. This simply means that we can obtain the wavelength of a wave by calculating the distance between two crest i.e 
Wavelength = distance between each crest. 
From the question given above, we were told that the distance between each crest is 2.43 m. 
Therefore, the wavelength of the wave is 2.43 m