The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. starting with 130 grams of a radioactive isotope, how much will be left after 5 half-lives?

use the calculator provided and round your answer to the nearest gram.

= 4 grams

Step-by-step explanation:

The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass.

Therefore, using the formula;

N = O × (1/2)^n ; where N is the new mass, O is the original mass, and n is the number of half lives.

In this case;

N = 130 × (1/2)^5

   = 130 × 1/32

   = 4.0625

   ≈ 4 g

step-by-step explanation:

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1. sometimes

2.   never

3   .08c = 7.50+.05c   250 pages

step-by-step explanation:

1.   sometimes

the theoretical probability of rolling a 1 is 1/6.   perhaps you got really lucky and never rolled a 1   in those 60 times.   your experimental probability is 0.   or perhaps you rolled a 1   20 times.   your experimental probability is 20/60 is 1/3.     it really just depends on how you rolled in that experiment.

2.   never

the probability of the event occurring is 1.   that is being 100 % sure it will happen.   that is the maximum amount of confidence we have.

3.   no customer card cost:   .08 times number of pages

customer card cost:   7.50 + .05 times number of pages

we want to find when it costs the same amount, so we will set these equal

let c = number of pages

.08c = 7.50+.05c

subtract .05c from each side

.08c-.05c = 7.5+.05c-.05c

.03c=7.5

divide each side by .03

.03c/.03 = 7.5/03

c =250  

the cost is the same at 250 pages