Patterns and functions

A bone fragment was found from an elk which had died 90 years before. What percent of Pb-210 remains? The half-life if Pb-210 is

Bess [88]

Answer:

about 5.9%

Step-by-step explanation:

We assume that the original amount of Pb-210 present at death decays at the given rate. The fraction (f) remaining is multiplied by 1/2 every 22 years, so can be modeled by ...

f = (1/2)^(t/22) . . . . . where t is in years after death

Then, for t=90, the remaining fraction is ...

f = (1/2)^(90/22) ≈ 0.05868 ≈ 5.9%

7 0

3 years ago

Help me pls i have a test soon

erik [133]

Answer:

I believe it is true, false, true, true.

Step-by-step explanation:

there are no green marbles, there are way more yellow marbles then even blue and red combined, you could get a blue one being the odds 5/16, and there are only 2 red marbles so it is unlikely that you choose red. I hope this helps!

4 0

2 years ago

Read 2 more answers

Simplify the following 3/5×(7/10+2/5)/ 5 2/3+1 3/8-2 1/4

Inessa [10]

Answer:

(-2579)/3400

Step-by-step explanation:

Simplify the following:

3/5 (7/10 + 2/5)/(5 + 2/3) + 1 + 3/8 - (2 + 1/4)

(3 (7/10 + 2/5)/(5 + 2/3))/5 = (3 (7/10 + 2/5))/(5 (5 + 2/3)):

(3 (7/10 + 2/5))/(5 (2/3 + 5)) + 1 + 3/8 - (2 + 1/4)

Put 5 + 2/3 over the common denominator 3. 5 + 2/3 = (3×5)/3 + 2/3:

(3 (7/10 + 2/5))/(5 (3×5)/3 + 2/3) + 1 + 3/8 - (2 + 1/4)

3×5 = 15:

(3 (7/10 + 2/5))/(5 (15/3 + 2/3)) + 1 + 3/8 - (2 + 1/4)

15/3 + 2/3 = (15 + 2)/3:

(3 (7/10 + 2/5))/(5 (15 + 2)/3) + 1 + 3/8 - (2 + 1/4)

15 + 2 = 17:

(3 (7/10 + 2/5))/(5×17/3) + 1 + 3/8 - (2 + 1/4)

Put 7/10 + 2/5 over the common denominator 10. 7/10 + 2/5 = 7/10 + (2×2)/10:

(3 7/10 + (2×2)/10)/((5×17)/3) + 1 + 3/8 - (2 + 1/4)

2×2 = 4:

(3 (7/10 + 4/10))/((5×17)/3) + 1 + 3/8 - (2 + 1/4)

7/10 + 4/10 = (7 + 4)/10:

(3 (7 + 4)/10)/((5×17)/3) + 1 + 3/8 - (2 + 1/4)

7 + 4 = 11:

(3×11/10)/(5×17/3) + 1 + 3/8 - (2 + 1/4)

5×17/3 = (5×17)/3:

(3×11/10)/((5×17)/3) + 1 + 3/8 - (2 + 1/4)

3×11/10 = (3×11)/10:

((3×11)/10)/((5×17)/3) + 1 + 3/8 - (2 + 1/4)

Multiply the numerator by the reciprocal of the denominator, ((3×11)/10)/((5×17)/3) = (3×11)/10×3/(5×17):

(3×11×3)/(5×17×10) + 1 + 3/8 - (2 + 1/4)

5×17 = 85:

(3×11×3)/(85×10) + 1 + 3/8 - (2 + 1/4)

85×10 = 850:

(3×11×3)/850 + 1 + 3/8 - (2 + 1/4)

3×11 = 33:

(33×3)/850 + 1 + 3/8 - (2 + 1/4)

33×3 = 99:

99/850 + 1 + 3/8 - (2 + 1/4)

Put 2 + 1/4 over the common denominator 4. 2 + 1/4 = (4×2)/4 + 1/4:

99/850 + 1 + 3/8 - (4×2)/4 + 1/4

4×2 = 8:

99/850 + 1 + 3/8 - (8/4 + 1/4)

8/4 + 1/4 = (8 + 1)/4:

99/850 + 1 + 3/8 - (8 + 1)/4

8 + 1 = 9:

99/850 + 1 + 3/8 - 9/4

Put 99/850 + 1 + 3/8 - 9/4 over the common denominator 3400. 99/850 + 1 + 3/8 - 9/4 = (4×99)/3400 + 3400/3400 + (425×3)/3400 + (850 (-9))/3400:

(4×99)/3400 + 3400/3400 + (425×3)/3400 + (850 (-9))/3400

4×99 = 396:

396/3400 + 3400/3400 + (425×3)/3400 + (850 (-9))/3400

425×3 = 1275:

396/3400 + 3400/3400 + 1275/3400 + (850 (-9))/3400

850 (-9) = -7650:

396/3400 + 3400/3400 + 1275/3400 + (-7650)/3400

396/3400 + 3400/3400 + 1275/3400 - 7650/3400 = (396 + 3400 + 1275 - 7650)/3400:

(396 + 3400 + 1275 - 7650)/3400

| 1 | 1 | 1 |

| 3 | 4 | 0 | 0

| 1 | 2 | 7 | 5

+ | | 3 | 9 | 6

| 5 | 0 | 7 | 1:

(5071 - 7650)/3400

5071 - 7650 = -(7650 - 5071):

(-(7650 - 5071))/3400

| | | 14 |

| | 5 | 4 | 10

| 7 | 6 | 5 | 0

- | 5 | 0 | 7 | 1

| 2 | 5 | 7 | 9:

Answer: (-2579)/3400

4 0

4 years ago

What is 300+400. <br> I want to see how smart you are can you do this mentally????

n200080 [17]

Answer:

700

Step-by-step explanation:

Since 3 + 4 = 7, then 300 + 400 = 700

6 0

3 years ago

Read 2 more answers

3. Tiffani has a baseball

Nimfa-mama [501]

Answer:

Tiffani has 182 cards left.

Step-by-step explanation:

Find one-third (1/3) of 273:

1/3 x 273 = 91

Therefore, she sells 91 cards.

273 - 91 = 182 cards left

Hope this helps :)

3 0

3 years ago

Patterns and functions​

Patterns and functions