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Fantom [35]
3 years ago
10

Suppose you have a cache of radium, which has a half-life of approximately 1590 years. how long would you have to wait for 1/5 o

f it to disappear?
Mathematics
1 answer:
lubasha [3.4K]3 years ago
4 0
<span>You would have to wait 318 years for 1/5 (20%) of the Radium to disappear. 1590 is the point where half of the Radium would decay, so if you take 20% of that, it would equate out to 318 years. Radium has a long half life!</span>
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The coefficient of 8 · 2N is _____.
SSSSS [86.1K]
I believe the answer you are looking for is 2.
6 0
3 years ago
Read 2 more answers
Find the remainder when 1 + 2 + 2^2 + 2^3 + ... + 2^100 is divided by 7.<br><br> Thanks in advance!
Firlakuza [10]

Answer:

3.

Step-by-step explanation:

This is a geometric series so the sum is:

a1 * r^n - 1 / (r - 1)

= 1 * (2^101 -1) / (2-1)

= 2^101 - 1.

Find the remainder when 2^101 is divided by 7:

Note that 101 = 14*7 + 3 so

2^101 = 2^(7*14 + 3) =  2^3  * (2^14)^7 = 8 * (2^14)^7.

By Fermat's Little Theorem  (2^14) ^ 7 = 2^14 mod 7 = 4^7 mod 7.

So 2^101 mod 7 = (8 * 4^7) mod 7

                           = (8 * 4) mod 7

                            = 32 mod 7

                            = 4 = the remainder when 2^101 is divided by 7.

So the remainder when 2^101- 1 is divided by 7 is 4 - 1 = 3..

4 0
2 years ago
Mathius walked ⅜ mile to school. Eva walked ⅖ mile to school. How many more
zalisa [80]

Answer:

132ft

Step-by-step explanation:

Mathius Distance = 3/8 mile

Eva Distance        = 2/5 mile

1 mile = 5,280ft

1. Start by multiplying the mile distance of Mathius to the distance of 1 mile in feet.

5,280ft x 3/8 = 15840ft/8 = 1980ft

2. Do the same thing as number 1 but for Eva's distance now.

5,280ft x 2/5 = 10560ft/5 = 2112ft

3. Subtract Eva's Distance from Mathius' Distance for the answer.

2112ft (Eva) - 1980ft (Mathius) = <em>132ft</em>

7 0
2 years ago
If gasoline costs $3.28 per gallon, how much would 15.5 gallons cost?
Sauron [17]

Answer:

$50.84

Step-by-step explanation:

By multiplying $3.28 × 15.5 = $50.84

5 0
2 years ago
1. Which of the following sets of integers is arranged in order from LEAST to GREATEST?
gavmur [86]

Answer:

Last option:

(-13, -12, 9)

Step-by-step explanation:

Here you need to look at a number line.

(an infinite line with the zero in the middle, at the left we have the negative numbers which increase to the left, and at the right, we have the positive numbers that increase to the right)

for any two pair of numbers in the number line, the number at the right is larger than the number at the left.

So for example, -10 is at the left of -3

Then:

-10 < -3.

Then a set is ordered from least to greatest if:

first we have the largest negative numbers

then the smaller negative numbers

then the zero (if there is a zero)

then the smaller positive numbers

then the largest positive numbers.

The only set that meets this condition is the last one:

(-13, -12, 9)

Why the others not meet this condition?

in the first one we have -9 after 5, and we know that -9 < 5

in the second one we actually have an order from greatest to least.

in the third one we have -8 at the right of 12, and we know that -8 < 12

3 0
3 years ago
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