Number of ways , two contaminated and 8 non- contaminated farms be choosen is 3,304,845,180.
Permutation and Combination
Combination is a mathematical way to arranging the set of values randomly.
ⁿCᵣ = n! / r! (n-r)!
we have given that ,
total number of farms for lead contamination = 50
Number of farms have dangerously high level of lead = 8
so, number of non- containmated farms ( no high level of lead ) = 50-8 = 42
We have to find the number of ways to choose two contaminated farms and eight non- contaminated farms. Two containmated farms are selected from 8 containated farms and 8 non- contaminated farms are selected from 42 farms .
Number of ways for selecting two containmated farms = ⁸C₂ = 8!/2!×6! = 8×7/2 = 28
Number of ways for selecting eight non-containmated farms from 42 farms = ⁴²C₈
= 42! / 8! 34! = 42×41×---×35/8×7×----×1
= 118013185
The total number of ways to obtain 2 containmated farms and 8 non- contaminated farms in 10 farms selected is then product of number of ways to select the 2 containmated farms and number of ways to select 8 non-containmated farms .
= 118030185× 28 = 3,304,845,180
To learn more about Combination and Permutation, refer:
brainly.com/question/28065038
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