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kvv77 [185]
2 years ago
10

Kira received a $80 gift card for a coffee store. She used it in buying some coffee that cost $8.03 per pound. After buying the

coffee, she had $39.85 left on her card. How many pounds of coffee did she buy?
Mathematics
1 answer:
never [62]2 years ago
3 0

Answer:

5 pounds

Step-by-step explanation:

80 - 39.85 = 40.15

40.15 ÷ 8.03

= 5

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Strontium-90 has a half-life of 28.8 years. If you start with a 300-gram sample of strontium-90,
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Answer:  2.66 × 10⁻¹³

<u>Step-by-step explanation:</u>

First, use the decay formula   A=A_oe^{kt}   where

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  • A₀ is the initial amount (amount you started with)
  • k is the rate of decay (you need to solve for this)
  • t is the time

Given:

  • A = 1/2(300) = 150
  • A₀ = 300
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150=300e^{28.8k}\\\\0.5=e^{28.8k}\\\\ln(0.5)=ln(e^{28.8k})\\\\ln(0.5)=28.8k\\\\\\\dfrac{ln(0.5)}{28.8}=k\\\\\\\large\boxed{-0.0240676=k}\\

Next, input the k-value and the new t-value to solve for A.

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5 0
3 years ago
Select the correct answer.
Naddik [55]
You use the FOIL method, and how you do this is -

(x - 7) (x + 8)

Multiply the first x by both numbers in the second factor. Which means, you multiply x by x and 8, the two in (x + 8).

With this, you get -
x^2 + 8x

Then do the same thing with -7.

-7x - 56

Then combine the two.
x^2 + 8x - 7x - 56

Combine like terms.

x^2 + x - 56

So now, 7 x 8 is 56
And -7 + 8 would be 1. And that is the value of “x” which is b in the form a^2x + bx + c.

Now with this, you take those two numbers and make the factors =
(x + 8) (x - 7)

Then you set these equal to 0.

x + 8 = 0

Subtract the 8 from both sides.

x = -8

————

x - 7 = 0

Add the 7 on both sides.

x = 7

Answer: A
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3 years ago
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-BARSIC- [3]

Answer:

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Step-by-step explanation:

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When the denominator and numerator are equal, it means?
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The fraction is one whole aka one
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Answer:

The answer is 16, I am pretty sure.

Step-by-step explanation:

I am soo sorry if it is wrong.

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3 years ago
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