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Semenov [28]
3 years ago
11

A small combination lock on a suitcase has 4 ​wheels, each labeled with the 10 digits 0 to 9. how many 4 digit combinations are

possible if no digit is​ repeated? if digits can be​ repeated? if successive digits must be​ different?
Mathematics
1 answer:
tamaranim1 [39]3 years ago
8 0
This is the easiest way to solve this problem:

Imagine this represents how many combinations you can have for each of the 4 wheels (each blank spot for one wheel): __ __ __ __

For the first situation it says how many combos can we make if no digits are repeated.
We have 10 digits to use for the first wheel so put a 10 in the first slot 
10 __ __ __
Since no digit can be repeated we only have 9 options for the second slot
10 9_ __ __
Same for the third slot, so only 8 options
<u>10</u> <u> 9 </u> <u> 8 </u> __
4th can't be repeated so only 7 options left
<u>10</u> <u> 9 </u> <u> 8 </u> <u> 7 
</u><u>
</u>Multiply the four numbers together: 10*9*8*7 = 5040 combinations


For the next two do the same process as the one above.

If digits can be repeated? You have ten options for every wheel so it would look like this: <u>10</u> <u>10</u> <u>10</u> <u>10
</u>
10*10*10*10 = 10,000 combinations

If successive digits bust be different?
We have 10 for the first wheel, but second wheel only has 9 options because 2nd number can't be same as first. The third and fourth wheels also has 9 options for the same reason.

<u>10</u> <u> 9</u><u> </u> <u> 9 </u> <u> 9 </u>

10*9*9*9 = 7290 combinations






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Which set of sides will make a triangle
ElenaW [278]

Answer:

the third one 10 cm, 9cm 9cm

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A meteorologist measures the angle of elevation of a weather balloon is 41 degrees. A radio signal from the balloon indicates th
I am Lyosha [343]
You can draw a diagram of the situation, representing it by a right triuangle.

In the right triangle the hypotenuse is the distance indicated by the radio signal, 1503 m, and the angle is 41°.

The opposed leg to 41° is the height of the ballon.

Then you can use the sine trigonometric function.

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4 0
3 years ago
HELP!
wel

Answer:

1. 6w+6=48

2. n = 9

3. 2x+2 = 5.64

4. 2x-3 = 7.80

5. 2x+6 = 30

6. 3x+3 = 153

7. 2x - 6 = 14

8. 3x + 6 = 54

9. 1424 = 356*t

Step-by-step explanation:

1.

Let the width be w, then twice the width is 2w. But our length is 3 more than twice the width, implying that our length will be 2w+3.

The perimeter of a rectangle is given by the formula;

p = 2(length + width)

2(2w+3+w) = 48

6w+6=48 is our required equation.

2.

Fifteen more than four times a number is 6 more than five times the number. Use "n" for the number.

We first evaluate, Fifteen more than four times a number;

since our number is n, the above statement can be written mathematically as,

4n + 15

The next step we evaluate; five times the number,

5n

In the final step we compare these two expression and solve for n;

we have been told that; Fifteen more than four times a number is 6 more than five times the number. This implies;

4n + 15 - 5n = 6

-n = -9

n = 9

3.

Let the amount paid by Martha be x. Therefore, the amount paid by Sally would be x+2 since she paid 2 more than Martha. The total amount paid by both is;

x+x+2 = 2x+2

The required equation is thus;

2x+2 = 5.64

4.

We let the amount spent by Tim be x. This would mean that Bob spent x-3 since we are told that Bob paid $3 less than Tim. Therefore, the total amount spent by Bob and Tim in terms of x is;

x+x-3 = 2x-3

Therefore, the required equation would be;

2x-3 = 7.80

5.

We let the number of men be x, then the number of women would be x+6 since we are told that there were six more women on the committee than men. The total number of people on the committee in terms of x is thus;

x+x+6 = 2x+6

Therefore, our required equation would be;

2x+6 = 30

6.

Three consecutive integers have the sum of 153.

We let the three consecutive integers be;

x, x+1, and x+2

The difference between consecutive integers is usually 1.

The sum of the above integers in terms of x would be;

x+x+1+x+2 = 3x+3

Therefore, our required equation would be;

3x+3 = 153

7. Five times the first of three consecutive even integers is fourteen more than three times the second.  

We let the first even integer be x. The second even integer would be x+2 while the third one would be x+4. The difference between two consecutive even integers is always 2. Now Five times the first of three consecutive even integers would be;

5*x = 5x

On the other hand, three times the second even integer would be;

3*(x+2) = 3x + 6

Now, we are told that 5x exceeds 3x + 6 by 14. Therefore, we can write;

5x - (3x +6) = 14

2x - 6 = 14

Which is the required equation

8. The sum of three consecutive even integers is fifty-four.

We let the first even integer be x. The second even integer would be x+2 while the third one would be x+4. The difference between two consecutive even integers is always 2. The sum of the three consecutive even integers in terms of x would be;

x+x+2+x+4 = 3x+6

The required equation would thus be;

3x + 6 = 54

9. An airplane flies at a rate of 356 km/h. The plane travels a total distance of 1424 km. (Use Distance = Rate * Time for your equation.)

The distance traveled by the plane is given as 1424 while its      rate or speed is 356. We let t denote the time it took the plane to travel the given distance at the given rate. Using the equation Distance = Rate * Time, we can write the following equation in t;

1424 = 356*t

Which is our required equation.

3 0
3 years ago
Find the length of MN.<br> A) 7 <br> B) 25 <br> C) 32 <br> D) 39
MrRissso [65]

Step-by-step explanation:

Answer C)

Explanation:

MN + NP = MP

MP = 39

Therefore, 4(x + 5) + 2x + 1= MP

So, 4(x + 5) + 2x + 1= 39

(4x + 20) + 2x +1 = 39

So, (4x + 2x) + (20 + 1) = 39

6x + 21 = 39

Addition changes to Subtraction

So, 6x = 39 - 21

6x = 18

Multiplication changes to Division

x= 18/6

x=3

Therefore MN = 4(x + 5)

So, 4(3 + 5) = 4(8)

4(8) = 32

Therefore, MN = 32

Hope this helps!

3 0
3 years ago
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