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malfutka [58]
3 years ago
13

Isabella save 2 nickels today, if she doubles the number of Nicole, she saves every day, how many days, including today, will it

take her to save more than 500 nickels?
Mathematics
1 answer:
Elden [556K]3 years ago
3 0

Answer:

  8 days

Step-by-step explanation:

On day 8, Isabella will save 256 nickels, bringing her total to 510.

_____

The number of nickels saved on day n is 2^n. The total is 2^(n+1)-2.

_____

The above can be written down from your knowledge of binary sequences. If you want a more formal development, read on.

__

The number of nickels saved on day n is a geometric sequence with first term 2 and common ratio 2. The n-th term of the sequence is ...

  an = a1·r^(n-1) = 2·2^(n-1) = 2^n

The sum of n terms of the sequence is ...

  S = a1(r^n -1)/(r -1) = 2(2^n -1)/(2-1)

  S = 2^(n+1) -2

__

We want S > 500, so ...

  500 < 2^(n+1) -2

  502 < 2^(n+1)

  251 < 2^n

  log(251) < n·log(2)

  n > log(251)/log(2)

  n > 7.97 . . . . . . . . 8 days or more to save more than 500 nickels

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DaniilM [7]

Answer:

x = 3

Step-by-step explanation:

Given

7(x + 2) - 5 = 30 ( add 5 to both sides )

7(x + 2) = 35 ( divide both sides by 7 )

x + 2 = 5 ( subtract 2 from both sides )

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3 0
3 years ago
Two circles with different radii have chords AB and CD, such that AB is congruent to CD. Are the arcs intersected by these chord
emmainna [20.7K]

The arcs intersected by these chords are not congruent.

Given that two circles with different radii have chords AB and CD, such that AB is congruent to CD.

Let r₁ and r₂ be the radii of two different circles with centers O and O' respectively.

Assuming that the each of the ∠АОВ  and ∠CO'D is less than or equal to π.

Then, we have isosceles triangle AOB and CO'D such that,

AO = OB = r₁,

CO' = O'D = r₂,

Let us assume that r₁< r₂;

We can see that arc(AB) intersected by AB is greater than arc(CD), intersected by the chord CD;

arc(AB) > arc(CD)      .......(1)

Indeed,

arc(AB) = r₁ angle (AOB)

arc(CD) = r₂ angle (CO'D)

So, we have to prove that ;

∠AOB >∠CO'D       ......(2)

Since each angle is less than or equal to π, and so

∠AOB/2  and ∠CO'D/2 is less than or equal to π

it suffices to show that :

tan(AOB/2) >tan(CO'D/2) ......(3)

From triangle AOB :

tan(AOB/2) = AB/(2*r₁)

tan(CO'D/2) = CD/(2*r₂)

Since AB = CD and r₁ < r₂ (As obtained from the result of (3) ), therefore, arc(AB) > arc(CD).

Hence, for two circles with different radii have chords AB and CD, such that AB is congruent to CD but the arcs intersected by these chords are not congruent.

Learn more about congruent from here brainly.com/question/1675117

#SPJ1

6 0
2 years ago
Solve for X, 132 is an exterior angle. Show work please!
Darina [25.2K]

Answer:

105/9

Step-by-step explanation:

180 - 132 = 48 degrees

180 - 48 - 45

= 180 - 93

= 87 degrees

<2 = 180 - 87

= 93 degrees

=> 9x - 12 = 93

=> 9x = 105

=> x = 105/9

6 0
2 years ago
Read 2 more answers
What is the x-intercepts of the graph of y = 12x-5x-2
devlian [24]
Hey there!

First, we see that it's already written in slope intercept, y = mx + b where m is the slope and b is the y intercept, we just need to simplify the like terms on the right. We have:

y = 12x-5x-2
y = 7x - 2

Now that we have it in slope intercept form, whenever we have an x intercept, since it is crossing the x axis, there's no y value. We plug in 0 for y:

0 = 7x - 2
2 = 7x
2/7 = x

The x intercept is (2/7, 0)

Hope this helps!
6 0
3 years ago
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Kay [80]
Do you have an answer? What do you think it is?
6 0
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