DessB
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In how many ways can Tim draw a red or a green marble from a jar containing 20 red marbles and 4 green marbles?
80
24
16
4

Respuesta :

sawyerk0826
I believe the answer is 24
kudzordzifrancis
The number of ways we can choose from n objects picking r at a time is given by the formula;

[tex]nC_r = \frac{n ! }{(n - r) ! r ! } [/tex]

Number of ways Tim can draw 1 red marble from 20 red marbles is

[tex]20C_1 = \frac{20! }{(20 - 1) ! 1 ! } = \frac{20 \times 19 ! }{19 ! 1! } = 20[/tex]

Number of ways Tim can draw 1 green marble from 4 green marbles is

[tex]4C_1 = \frac{4! }{(4 - 1) ! 1 ! } = \frac{4 \times 3 ! }{3 ! 1! } = 4[/tex]

Number of ways Tim can draw a red or green marble is

[tex]20C_1 +4C_1 = 20 + 4 = 24[/tex]

Hence the correct answer is 24.

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