2/3 of a number is 28 what is that number

What is the sum of the geometric sequence -3, 18, -108, ... if there are 8 terms

creativ13 [48]

Answer:

Step-by-step explanation:

common ratio=18/-3=-108/18=-6, a=-3

sn=a(r^n-1)(r-1)

sn=-3((-6)^n-1)(-6-1)

sn=-3(-6)^8-1)/(-7)

s8=-3(1679615)/(-7)

s8=719836

6 0

2 years ago

There are 3 red pens, 4 blue pens, 2 Blac pens, and 5 green pens in drawer, suppose you choose a pen at random

Alenkasestr [34]

Answer:

1. 3/14

2. 2/7

3. 1/7

4. 5/14

5. 11/14

6. 9/14

Step-by-step explanation:

first get the total number of pens

3 red pens + 4 blue pens + 2 black pens + 5 green pens =

14 total number of pens

1. What is the probability that the pen chosen red?

3 red pens out of a total of 14 pens = 3/14

2. What is the probability that the pen chosen is blue?

4 blue pens out of a total of 14 pens = 4/14 -> simplified -> 2/7

3. What is the probability that the pen chosen is black?

2 black pens out of a total of 14 pens = 2/14 -> simplified -> 1/7

4. What is the probability that the pen chosen is green?

5 green pens out of a total of 14 pens = 5/14

5. What is the probability that the pen chosen is NOT red?

of the 3 red pens, 4 blue pens, 2 black pens and 5 green pens

4 blue pens, 2 black pens and 5 green pens are NOT red

4 blue pens + 2 black pens + 5 green pens =

11 total number of pens that are NOT red

11 total number of pens that are NOT red out of a total of 14 pens = 11/14

6. What is the probability that the pen chosen is NOT green?

of the 3 red pens, 4 blue pens, 2 black pens and 5 green pens

the 3 red pens, 4 blue pens, 2 black pens are NOT green

3 red pens + 4 blue pens + 2 black pens =

9 total number of pens that are NOT green

9 total number of pens that are NOT green out of a total of 14 pens = 9/14

gathmath.com

6 0

2 years ago

Read 2 more answers

Three fourths of the fruit in a refrigerator are apples. There are 24 apples in the refrigerator. How many pieces of fruit are i

Eva8 [605]

3/4=24 so 1/4=8 therefore 4/4=32

8 0

2 years ago

Ken predicts that the average temperature will be −5°C in December. If he predicts the temperature will rise 6°C in January and

ipn [44]

Answer:

The equations [(-5) + (-3)] + 6 = -2 and [6 + (-5)] + (-3) = -2 he can use to find the sum of the temperatures for those months ⇒ 3rd , 5th

Step-by-step explanation:

i took the assignment

7 0

3 years ago

The prior probabilities for events A1 and A2 are P(A1) = 0.20 and P(A2) = 0.80. It is also known that P(A1 ∩ A2) = 0. Suppose P(

Umnica [9.8K]

Answer:

(a) $A_1$ and $A_2$ are indeed mutually-exclusive.

(b) $\displaystyle P(A_1\; \cap \; B) = \frac{1}{20}$ , whereas $\displaystyle P(A_2\; \cap \; B) = \frac{1}{25}$ .

(c) $\displaystyle P(B) = \frac{9}{100}$ .

(d) $\displaystyle P(A_1 \; |\; B) \approx \frac{5}{9}$ , whereas $P(A_1 \; |\; B) = \displaystyle \frac{4}{9}$

Step-by-step explanation:

$P(A_1 \; \cap \; A_2) = 0$ means that it is impossible for events $A_1$ and $A_2$ to happen at the same time. Therefore, event $A_1$ and $A_2$ are mutually-exclusive.

By the definition of conditional probability:

$\displaystyle P(B \; | \; A_1) = \frac{P(B \; \cap \; A_1)}{P(B)} = \frac{P(A_1 \; \cap \; B)}{P(B)}$ .

Rearrange to obtain:

$\displaystyle P(A_1 \; \cap \; B) = P(B \; |\; A_1) \cdot P(A_1) = 0.25 \times 0.20 = \frac{1}{20}$ .

Similarly:

$\displaystyle P(A_2 \; \cap \; B) = P(B \; |\; A_2) \cdot P(A_2) = 0.80 \times 0.05 = \frac{1}{25}$ .

Note that:

$\begin{aligned}P(A_1 \; \cup \; A_2) &= P(A_1) + P(A_2) - P(A_1 \; \cap \; A_2) = 0.20 + 0.80 = 1\end{aligned}$ .

In other words, $A_1$ and $A_2$ are collectively-exhaustive. Since $A_1$ and $A_2$ are collectively-exhaustive and mutually-exclusive at the same time:

$\displaystyle P(B) = P(B \; \cap \; A_1) + P(B \; \cap \; A_2) = \frac{1}{20} + \frac{1}{25} = \frac{9}{100}$ .

By Bayes' Theorem:

$\begin{aligned} P(A_1 \; |\; B) &= \frac{P(B \; | \; A_1) \cdot P(A_1)}{P(B)} \\ &= \frac{0.25 \times 0.20}{9/100} = \frac{0.05 \times 100}{9} = \frac{5}{9}\end{aligned}$ .

Similarly:

$\begin{aligned} P(A_2 \; |\; B) &= \frac{P(B \; | \; A_2) \cdot P(A_2)}{P(B)} \\ &= \frac{0.05 \times 0.80}{9/100} = \frac{0.04 \times 100}{9} = \frac{4}{9}\end{aligned}$ .

6 0

2 years ago

2/3 of a number is 28 what is that number​

2/3 of a number is 28 what is that number