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3 years ago

Padlock has a 4 digit key code

Mathematics

1 answer:

scoundrel [369]3 years ago

5 0

Answer:

5739

Step-by-step explanation:

We start by using the information:

4268 - Has no correct digits

This means that the digits 2,4,6 and 8 are not in the combination. (A)

Next, we analyze the information:

2657 - has two correct digits but neither are in the correct place

From what we said above, 2 and 6 are NOT present in the combination - so the correct digits here must be 5 and 7. However, they are not in the correct place. (B)

0415 - Has one correct digit but it's in the wrong place

From what we said in (B), the correct digit here must be 5 - however, it's not in the correct place. So, the 5 should be either the 1st digit or the 2nd digit of the combination. Also, since there is only 1 correct digit here, we can also exclude the digits 0 and 1 from the combination. (C)

1749 - Has two correct digits, both in the correct place.

Since we said that 7 is a correct digit (A) and 1 and 4 are not part of the combination (B and C), the other correct digit here must be 9. Since the 7 and the 9 are at the correct place, the combination now is:

X 7 X 9

We also know that 5 is another correct digit (B), and it is not at the 3rd place (C), therefore it must be at the 1st place; so we have:

5 7 X 9

Finally, we notice that so far we have excluded the following digits:

0, 1, 2, 4, 6, 8

And since 5,7 and 9 are already present, the only missing digit is 3; so the combination is:

5739

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Please help me with the below question.

VMariaS [17]

By letting

$y = \displaystyle \sum_{n=0}^\infty c_n x^{n+r}$

we get derivatives

$y' = \displaystyle \sum_{n=0}^\infty (n+r) c_n x^{n+r-1}$

$y'' = \displaystyle \sum_{n=0}^\infty (n+r) (n+r-1) c_n x^{n+r-2}$

a) Substitute these into the differential equation. After a lot of simplification, the equation reduces to

$5r(r-1) c_0 x^{r-1} + \displaystyle \sum_{n=1}^\infty \bigg( (n+r+1) c_n + (n + r + 1) (5n + 5r + 1) c_{n+1} \bigg) x^{n+r} = 0$

Examine the lowest degree term $\left(x^{r-1}\right)$ , which gives rise to the indicial equation,

$5r (r - 1) + r = 0 \implies 5r^2 - 4r = r (5r - 4) = 0$

with roots at r = 0 and r = 4/5.

b) The recurrence for the coefficients $c_k$ is

$(k+r+1) c_k + (k + r + 1) (5k + 5r + 1) c_{k+1} = 0 \implies c_{k+1} = -\dfrac{c_k}{5k+5r+1}$

so that with r = 4/5, the coefficients are governed by

$c_{k+1} = -\dfrac{c_k}{5k+5} \implies \boxed{g(k) = -\dfrac1{5k+5}}$

c) Starting with $c_0=1$ , we find

$c_1 = -\dfrac{c_0}5 = -\dfrac15$

$c_2 = -\dfrac{c_1}{10} = \dfrac1{50}$

so that the first three terms of the solution are

$\displaystyle \sum_{n=0}^2 c_n x^{n + 4/5} = \boxed{x^{4/5} - \dfrac15 x^{9/5} + \frac1{50} x^{13/5}}$

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laila [671]

Answer

Step-by-step explanation:

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A restaurant offers a combo special with 3 different sandwiches, 2 different salads, and 5 different drinks. From how many diffe

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Answer:

30 ways

Step-by-step explanation:

Given the following information:

3 different sandwiches
2 different salads
5 different drinks

Let assume that the combo contains: 1 sandwich, 1 salad, and 1 drink

Hence, we have:

The total possible ways of choosing sandwiches she can choose is: 3

The total possible ways of choosing salads she can choose is: 2

The total possible ways of choosing drinks she can choose is: 5

=> Total ways = 3*5*2 = 30 ways or there are 30 different combos Keisha can choose

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3 years ago

Howard is designing a chair swing ride. The swing ropes are 5 meters long, and in full swing they tilt in an angle of 29 degrees

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Answer:

Step-by-step explanation:7.12 meters tall

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A man travelled 3/8 of his journey by a rail 1/4 by a taxi 1/8 by and the remaining 2km on foot what is the length of his total

Burka [1]

The man travelled in different ways: by rail, by taxi, by ___ and by foot. I placed a blank there because there seems to be a missing word in the given problem above. For sample purposes, let's just assume that is travel by bus.

Since all of these travels are equal to 1 whole journey, you can express each travel as a fraction. When you add them up, the answer would be 1. So,

3/8 + 1/4 + 1/8 + x = 1

The variable x here denotes the fraction of his travel by foot. We are only given the exact distance travelled on foot which is 2 km. We have to find the fraction of the travel by foot to determine the length of the total distance travelled. Solving for x,

x = 1 - 3/8 - 1/4 - 1/8
x = 1/4

That means that the travel by foot comprises 1/4 of the whole journey. Thus,

Let total distance be D.

1.4*D = 2 km
D = 8 km

Therefore, the man travelled a total of 8 kilometers.

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