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serious [3.7K]
2 years ago
7

Consider all seven-digit numbers that can be created from the digits 0-9 where the first and last digits must be odd and no digi

t can
repeat. What is the probability of choosing a random number that starts with 5 from this group? Enter a fraction or round your answer to
4 decimal places, if necessary.
Mathematics
2 answers:
Yuliya22 [10]2 years ago
7 0

Answer:

1/4 or 0.25

Step-by-step explanation:

The total possibilities of any 7 digit number using 0-9 is :

9×10×10×10×10×10×10=9000000

To work out the total possibilities in this question :

We look at the conditions :

The first digit can only be 5 numbers :

1 , 3 , 5 , 7 , 9

Now we subtract 5 from 9 :

9-5 = 4

Since no repeats for 2 , 3 , 4, 5, 6:

9 , 8 , 7 , 6 , 5,  

5 possibilities for the last digit :

Total possibilities for this code :

4 × 9 × 8 × 7 × 6 × 5 × 5 = 302400

If it begins with 5 that is only 1 possibility for the first digit

1 × 9 × 8 × 7 × 6 × 5 × 5 = 75600

Now we make a fraction :

75600÷302400

Dividing top and bottom by 75600 gives you 1/4 or 0.25

Hope this helped and have a good day

postnew [5]2 years ago
4 0

Answer:

Step-by-step explanation:

Comment

The first digit and the last digit are both odd. That tells you that so far what you have is one of 5 digits for the first digit and and one of 4 for the last digit. 4 because you can't repeat the first digit.

5, , , , , ,4

2 digits are gone 8 remain.

5* 8 * 7* 6* 5* 4* 4 = 134400

Part 2

Only one number can go at the beginning, and that is a 5. Everything else remains the same.

1 * 8 * 7 * 6 *5 * 4 * 4 = 26880

P(picking a number beginning with a 5 is  25880 /13440) = 0.2

You might be interested in
What two numbers multiply to negative 8 but add to negative 7
Amiraneli [1.4K]
Let "a" and "b" be the two numbers
So a*b=-8 and a+b=-7
Therefore S=-7 and P=-8
Using (x^2)-S+P=0 => (x^2)-(-7)+(-8)=0 => (x^2)+7-8=0
By factorizing we get (x+8)(x-1)=0
So a can be either -8 or 1 and b can be 1 or -8 
Meaning that the two numbers are -8 and 1.
6 0
3 years ago
Help me plz thanks my friend
NikAS [45]

Answer:

I believe the answer would be 21.

Step-by-step explanation:

the shadow of the tall flag is three times the small flag, so the height of the flag should also be three times the height.  which is 21

6 0
3 years ago
The height of a triangle is 8 centimeters greater than half its base. The area of the triangle is 48 square centimeters what is
emmainna [20.7K]

Answer:

base = 8 cm

height = 12 cm

Step-by-step explanation:

We will need the formula for area of a trianlge, which is

A = (1/2)bh    where b is the base, and h is the height

We are given two formulas...

"The height of a triangle is 8 centimeters greater than half its base" becomes

  h = (1/2)b + 8

"The area of the triangle is 48 square centimeters" becomes

48 = (1/2)bh

Plug the first formula into the second to solve for h

48 = (1/2)b[(1/2) + 8]             (h becomes (1/2)b + 8)

Now solve for b

48 = (1/4)b² + 4b

**This is a quadratic euquation.  Solve using factoring...

(1/4)b² + 4b - 48 = 0       (subtract 48 from both sides)

b² + 16b - 192  =  0       (multiply by 4 so b² is by itself, it's easier to factor this way)

Now factor...

(b + 24)(b - 8) = 0       (you need two numbers that add to 16 and multiply to -192)

Set each binomial equal to zero and solve for b

b + 24 = 0          

    b = -24    

**this anwser is not valid because b is a length, and you can't have negative length

b - 8 = 0

  b = 8        

Since the other solution is invalid, the base is b

If the base is b, then the height is...

h = (1/2)b + 8

 

   h = (1/2)(8) + 8

     h = 4 + 8

 

         h = 12

8 0
3 years ago
You have 42,784 grams of a radioactive kind of curium. If its half-life is 18 years, how much will be left after 72 years?
s344n2d4d5 [400]

Answer:

2,674.14 g

Step-by-step explanation:

Recall that the formula for radioactive decay is

N = N₀ e^(-λt)

where,

N is the amount left at time t

N₀ is the initial amount when t=0, (given as 42,784 g)

λ = coefficient of radioactive decay

  = 0.693 ÷ Half Life

  = 0.693 ÷ 18

  = 0.0385

t = time elapsed (given as 72 years)

e = exponential constant ( approx 2.7183)

If we substitute these into our equation:

N = N₀ e^(-λt)

= (42,787) (2.7183)^[(-0.0385)(72)]

= (42,787) (2.7183)^(-2.7726)

=  (42,787) (0.0625)

= 2,674.14 g

6 0
3 years ago
Find the value of x.<br><br> Please help and can somebody tell me how to find x?
Olegator [25]

Answer:

x = 75°

Step-by-step explanation:

Sum of the interior angles of a triangle = 180°

Therefore,

78° + 27° + x° = 180°

Add like terms

105 + x = 180

105 + x - 105 = 180 - 105 (substraction property of equality)

x = 75°

4 0
3 years ago
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