5(x − 4)^2
5(x - 4)(x - 4)
5(x^2 - 8x + 16)
5x^2 - 40x + 80
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Answer: 
Step-by-step explanation:
Total horses = 6
Number of ways to choose top 3 finishers in order = 3! = 6
Number ways to select 3 horses out of 8 in order =
[By permutations]

Now, the probability that the gambler will win his bet =


Hence, the required probability = 