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3 years ago

If a single 20 sided dice is tossed once what is the probability of rolling a 15 or 17

1 answer:

6 0

For a single 20 sided dice, a chance to get a certain number would be 1/20. For 2 numbers it will be a 2/20 chance, which can be simplified to a 1/10 chance that you will roll a 15 or a 17.

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Solve the unknown viable 7c/12 + 5c/16=15/48 +c

Mashutka [201]

deconstructing
48 : 2 = 24
24 : 2 = 12
12 :2 = 6
6 : 2 = 3
3 : 3 = 1
2 * 2 * 2 * 2 * 3 = 48
...................................
16 : 2 = 8
8 : 2 = 4
4 : 2 = 2
2 : 2 = 1
2 * 2* 2 * 2 = 16
..................................
12 : 2 = 6 $\frac{7c}{12} + \frac{5c}{16} = \frac{15}{48} + c \\ \\ \frac{7c*4}{12*4} + \frac{5c*3}{16*3} - \frac{15}{48} = c \\ \\ \frac{28c + 15c}{48} - \frac{15}{48} = c \\ \\ 48c = 43c - 15 \\ \\ 48c - 43c = -15 \\ \\ 5c =- 15 \\ \\ c = -3
$ 
6 : 2 = 3
3 : 3 = 1
common denominator 48

5 0

3 years ago

Use the initial term and the recursive formula to find an explicit formula for the sequence an. Write your answer in simplest fo

Ipatiy [6.2K]

Answer:

$a_n = -11-14n$

Step-by-step explanation:

Given

$a_1 = -25$

$a_n = a_{n-1}-14$

Required

The explicit formula

First, calculate $a_2$

Set n=2; So:

$a_2 = a_{2-1}-14$

$a_2 = a_{1}-14$

Substitute -25 for $a_1$

$a_2 = -25-14$

$a_2 = -39$

Calculate the common difference (d)

$d = a_2 - a_1$

$d = -39 --25$

$d = -14$

So, the nth term is:

$a_n = a_1 + (n - 1)d$

$a_n = -25+ (n - 1)*-14$

Open bracket

$a_n = -25-14n + 14$

Collect like terms

$a_n = 14-25-14n$

$a_n = -11-14n$

4 0

2 years ago

The number obtained on rationalizing the denominator of 1/(√7--2) is

Slav-nsk [51]

$\frac{1}{ \sqrt{7} -(- 2)} \\ rationalizing \: \: \: the \: \: \: denominator \: \: \: we \: \: \: have \\ = \frac{1}{ \sqrt{7} + 2 } \times \frac{ \sqrt{7} - 2}{ \sqrt{7} - 2} \\ = \frac{ \sqrt{7} - 2}{ {( \sqrt{7} )}^{2} - {(2)}^{2} } \\ = \frac{ \sqrt{7} - 2 }{7 - 4} \\ = \frac{ \sqrt{7} - 2}{3}$