Bob is studying the effect of coral and sponge species on reef ecosystems using experiments in artificial square tanks. In each tank, he places 3 species of corals and 2 species of sponges. If there are 6 species of corals and 5 species of sponges to choose from, the minimum number of tanks required to test all combinations of 3 coral and 2 sponge species is _______ (Answer in integer)
This solution details the calculation for the minimum number of experimental tanks needed based on combinations of coral and sponge species for Bob's study.
The core task is to determine the total number of unique combinations possible when selecting a specific number of coral species and sponge species from larger sets. This requires applying the combination formula.
We use the combination formula, $C(n, k)$, which calculates the number of ways to choose $k$ items from a set of $n$ items without regard to the order of selection. The formula is:
$C(n, k) = \binom{n}{k} = \frac{n!}{k!(n-k)!}$Calculate the number of ways to choose 3 coral species from 6:
$C(6, 3) = \frac{6!}{3!(6-3)!} = \frac{6!}{3!3!} = \frac{6 \times 5 \times 4}{3 \times 2 \times 1} = 20$There are 20 distinct combinations for the coral species.
Calculate the number of ways to choose 2 sponge species from 5:
$C(5, 2) = \frac{5!}{2!(5-2)!} = \frac{5!}{2!3!} = \frac{5 \times 4}{2 \times 1} = 10$There are 10 distinct combinations for the sponge species.
Multiply the number of coral combinations by the number of sponge combinations to find the total minimum tanks needed:
$ \text{Minimum Tanks} = C(6, 3) \times C(5, 2) = 20 \times 10 = 200 $The minimum number of tanks required is 200.
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