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Tresset [83]
3 years ago
9

You have 12 coins, one of which is fake. The fake coin is indistinguishable from the rest except that it is heavier. Can you det

ermine which is the fake coin heavier using a balance scale and only 3 weighings?

Mathematics
2 answers:
Anton [14]3 years ago
5 0
Yep! 
Weighing #1: Start off by splitting the pile of 12 coins evenly into two piles, 6 in each pile. Put one pile on each side of the balance. The side that is weighed down has the fake coin it in. Ignore the other 6 coins.

Weighing #2: Now you have 6 coins left. Split the pile evenly again, 3 in each pile. Repeat the same process and put each pile on one side of the balance. The side that is weighed down has your fake coin in it. Ignore the other 3 coins.

Weighing #3: You have 3 coins left. Take two coins, whichever two you like, and weigh them. If they weigh the same, then the one you didn't weigh is the fake one. If one is heavier, then that heavier one is your fake coin.
KATRIN_1 [288]3 years ago
3 0
1) Divide 12 coins into 6 6
The heavier side contain the fake coin

2)Divide the 6 coins left by 3,you will get 2 coins per groups
Just put TWO groups of coins on the balance and keep the third group aside

**If two sides of the balance are balance,it means that the third group contain fake coin**
**If one side is heavier,that 2 coins contain fake coin**

3)Directly put the chosen 2 coins on each side and you can find out which is the fake one!

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​Claim: Most adults would erase all of their personal information online if they could. A software firm survey of 640 randomly s
tatyana61 [14]

Answer:

Given:

Sample size, n = 640

Since result showed that 99.2​% of them would erase all of their personal information online if they could, we have:

P' = 99.2% = 0.992

Let's take p = 50%

Our null and alternative hypothesis will be :

H0 : u = 0.5

H1 : u > 0.5

In this case we are to check for the test statistic.

\frac{P' - p}{\sqrt{p(1-p)/n}}

= \frac{0.992 - 50}{\sqrt{50(1-50)/640}}

= 24.9

Test statistic, Z = 24.893

In conclusion, the results are significantly high, which suggets there is suffcient evidence to support the claim that most adults would erase all of their personal information online.

7 0
3 years ago
Prove a/b is less than b/a when 0 < a <b
enyata [817]

\frac{a}{b} < \frac{b}{a} \implies \\ a^2 < b^2 \implies a-b

We are given that 0<a<b, which means that 0>-a>-b if you multiply it by -1, which means what's given by our inequality is true and we are done.

7 0
3 years ago
Transform both equations in each system of equations so that each coefficient is an integer.
inysia [295]
For the first one multiply each term by the LCM of 4 and 6, which is 12:-

15x -36 = 2y..................(1)

and second multiply by 5:-

2x + y = 9..............(2)

solving:-
from equation (2) y = 9-2x,  substitute  in equation (1):-

15x - 36 = 2(9-2x) = 18 - 4x
19x = 54
x = 54/19 = 2.84

so y =  9 - 2(2.84) = 3.32


4 0
3 years ago
Find the diagonal of a square whose sides are of the given measure.<br><br> Given =
Contact [7]

Answer:

7\sqrt{42}

Step-by-step explanation:

The diagonal is the hypotenuse of the right triangle with legs 7\sqrt{3}

Use Pythagoras' identity to solve for the diagonal d

The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is

d² = (7\sqrt{3})² + (7\sqrt{3})²

    = 147 + 147

    = 294 ( take the square root of both sides )

d = \sqrt{294} = 7\sqrt{42} ≈ 45.37 ( to 2 dec. places )

6 0
2 years ago
PLEASE HELP! Which points lie in the second quadrant? Check all that apply?
nevsk [136]

Answer:

is there picture?

Step-by-step explanation:

3 0
2 years ago
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