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3 years ago

Starting with 195 grams of a radioactive isotope, how much will be left after 3 half-lives?

1 answer:

4 0

After one half-life: $\frac{1}{2}\times 195=97.5$ grams.

After two half-lives: $\frac{1}{2} \times 97.5=48.75$ grams.

After three half-lives: $\frac{1}{2} \times 48.75=24.375$ grams.

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Geometry Helps please (Only correct Answers only please) Thank you!

Elza [17]

Answer:

37.68 units³

Step-by-step explanation:

To calculate the volume of a cone, the formula is:

V = π x r² x ( h / 3 )

Simply input the corresponding numbers into the equation:

V = π x ( 2 )² x ( 9 / 3 )

V = π x 4 x ( 3 )

V = π x 12

V = 3.14 x 12

V = 37.68 units³

If we use 3.14 for pi, the answer comes out to 37.68 units³

6 0

3 years ago

After a birthday only 1/4 cake ramains what fraction is equivalent 1/4

victus00 [196]

Answer:

2/8, 3/12, 4/24, 5/20, 6/24, 7/28, 8/32, 9/36, 10/40, etc.

Step-by-step explanation:

3 0

3 years ago

What is 857/45 as a mixed number? having trouble with sixth grade math.

barxatty [35]

857/45 as a mixed number is 19 2/45

4 0

3 years ago

If 3 workers can paint a room in 2 hours, then approximately how long does it take 4 workers to paint the same room? Assume the

Olin [163]

It takes 1.5 hours for 4 workers to paint the same room

Solution:

Given that 3 workers can paint a room in 2 hours

To find: Time taken for 4 workers to paint the same room

Assume the time needed to paint the room is inversely proportional to the number of worker

$time $ \propto \frac{1}{\text { number of workers }}\\\\time =k \times \frac{1}{\text { number of workers }}$

Where, "k" is the constant of proportionality

3 workers can paint a room in 2 hours

Substitute number of workers = 3 and time = 2 hours

$time =k \times \frac{1}{\text { number of workers }}\\\\2 = k \times \frac{1}{3}\\\\k = 6$

Therefore,

$\text {time}=6 \times \frac{1}{\text { number of workers }}$

To find time taken for 4 workers to paint the same room, substitute number of workers = 4 in above expression

$time = 6 \times \frac{1}{4} = 1.5$

Thus it takes 1.5 hours for 4 workers to paint the same room

6 0

3 years ago

Read 2 more answers

I can't seem to figure this out

antiseptic1488 [7]

Answer:

c. 4

Step-by-step explanation:

tan (30)/1 = x/7 *cross multiply*

x = 7 (tan(30))

x = 4.04

x = 4

6 0

3 years ago