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3 years ago

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A political polling organization wishes to select a smaller focus group from a group of 7 Republicans, 10 Democrats, and 2 Indep

endents. In how many ways can the group be chosen if: (a) it will consist of 1 Republican and 4 Democrats?(b) it will consist of 2 Republicans, 2 Democrats, and 3 Independents?

1 answer:

Alina [70]3 years ago

7 0

Answer:

a) 1470 ways

b) 2835 ways

Step-by-step explanation:

the question is not correct, in the correct question The number of independents should be 3 not 2

there are 7 republicans, 10 democrats and 3 independents.

C(n,r) is the number of different combinations of n distinct objects taken r at a time.

C(n,r) = $\frac{n!}{(n-r)!r!}$

a) it will consist of 1 Republican and 4 Democrats

The number of ways this can be chosen is = C(7,1) × C(10,4) = $\frac{7!}{(7-1)!1!} * \frac{10!}{(10-4)!4!}$ = 7 × 210 = 1470 ways

(b) it will consist of 2 Republicans, 2 Democrats, and 2 Independents (consist of 2 independents not 3)

The number of ways this can be chosen is = C(7,2) × C(10,2) × C(2,2)

= $\frac{7!}{(7-2)!2!} * \frac{10!}{(10-2)!2!}* \frac{3!}{(3-2)!2!}$ = 21 × 45 × 3 = 2835 ways

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vampirchik [111]

$\displaystyle\lim_{h\to0}\frac{\tan\sqrt{x+h}-\tan x}h$

Employ a standard trick used in proving the chain rule:

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$\displaystyle\left(\lim_{h\to0}\frac{\tan\sqrt{x+h}-\tan x}{\sqrt{x+h}-\sqrt x}\right)\cdot\left(\lim_{h\to0}\frac{\sqrt{x+h}-\sqrt x}h\right)$

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$\displaystyle\lim_{h\to0}\frac{\tan\sqrt{x+h}-\tan\sqrt x}{\sqrt{x+h}-\sqrt x}=\lim_{h'\to0}\frac{\tan(y+h')-\tan y}{y+h'-y}=\lim_{h'\to0}\frac{\tan(y+h')-\tan y}{h'}$

which in turn is the derivative of $\tan y$ , another limit you probably already know how to compute. We'd end up with $\sec^2y$ , or $\sec^2\sqrt x$ .

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3 years ago

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3 years ago

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(This is because 4 out of 12 marbles are red and412412 reduces to 1313.

The probability of selecting a red marble the second time is 1313.

The marble selections are independent and you can multiply the two probabilities to get the following:

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2 years ago

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The parameters are:

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He makes 90% of the free throws, hence $p = 0.9$ .

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The probability that he makes exactly 1 is P(X = 1), hence:

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2 years ago

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