<u>x3</u>=<u>512
</u>3 3
x=170.66666666
Number of brown trout = 6
Number of lake trout = 18
Total number of trouts = 
Probability to catch a lake trout first time = 
As the fisherman let the trout go, so probability for the second time is =

Hence, the probability becomes=

= 
The probability to find the brown trout is 
as , 
= 
Answer: 720ways, 24ways
Step-by-step explanation:
Given the seven letter words "SYSTEMS", if E is always occurring before M it means E and M will always be together therefore they letter 'EM' will be taken as an entity to five us 6letters i.e SYST(EM)S.
This can then be arranged in 6!ways
6! = 6×5×4×3×2×1 = 720ways
Similarly, if the E somewhere before the M and the three Ss grouped consecutively, this means E and M must always be together as well as the Ss to give (SSS)YT(EM).
This means that the letters in the bracket can be taken as an entity to give a total of 4 entities. This can them be arranged in 4! ways.
4! = 4×3×2×1
4! = 24ways