If two of these shapes are randomly chosen, one after the other without replacement, what is the probability that both chosen will be triangles?

Respuesta :

Answer:

[tex]P(T_1\ n\ T_2) = \frac{2}{21}[/tex]

Step-by-step explanation:

From the comments in your question; we have

Stars = 4

Triangles = 5

Circles = 3

Squares = 3

Required  

Determine the probability of both shapes being triangles

First, calculate the total

[tex]Total = 4 + 5 + 3 + 3[/tex]

[tex]Total = 15[/tex]

Next, calculate the probability of the first selected shape being a triangle;

P(T₁) = Number of triangles divided by total number of shapes

[tex]P(T_1) = \frac{5}{15}[/tex]

[tex]P(T_1) = \frac{1}{3}[/tex]

Next, calculate the probability of the second selected shape being a triangle;

P(T₂) = Number of triangles divided by total number of shapes

Because it's probability without replacement. the number of triangle left is 4 and the number of shapes left is 14;

So:

[tex]P(T_2) = \frac{4}{14}[/tex]

[tex]P(T_2) = \frac{2}{7}[/tex]

Hence:

[tex]P(T_1\ n\ T_2) = P(T_1) * P(T_2)[/tex]

[tex]P(T_1\ n\ T_2) = \frac{1}{3} * \frac{2}{7}[/tex]

[tex]P(T_1\ n\ T_2) = \frac{2}{21}[/tex]

Hence, the required probability is [tex]\frac{2}{21}[/tex]

Answer:

2/21

Step-by-step explanation:

There are 4 stars, 5 triangles, 3 circles, and 3 squares

For the first drawing there are 5 triangles and a total of 15 shapes.

p(first triangle) = 5/15 = 1/3

Since there is no replacement, for the second drawing, and one triangle has been taken, now there are 4 triangles left and 14 total shapes left.

p(second triangle) = 4/14 = 2/7

p(two triangles) = p(first triangle) * p(second triangle)

p(two triangles) = 1/3 * 2/7

p(two triangles) = 2/21