A scientist has 20 grams of the radioactive isotope sodium-24. The isotope decays exponentially as shown in the table.
Time (hours)
Mass (grams)
un
15.9
10
12.6
15
10
20
7.9
25
6.3
30
5
Approximately what will the mass of the isotope be after 45 hours? A
A 1.5 grams
B. 2.5 grams
C. 3.5 grams
D
4.5 grams

How do you find the circumfrance of a circle?

Evaluate the expression for the given value of the variable. ∣-4b-8∣+∣-1-b^2 ∣+2b^3 ; b=-2

Carla was trying to decide what to do saturday evening. she has $100 available to spend for the evening. she has narrowed her choices down to these events: braves game, a concert of an artist she likes, or the georgia aquarium. admission to the braves game is $25, hot dogs cost $10, sodas cost $5. the concert costs $25 for admission, $20 for a souvernir t-shirt, and $10 for a soda. the georgia aquarium has the show of a lifetime with an all you can eat and drink that costs $100. carla does not want to take any driving chances, so in addition to the cost of the aquarium, she will also need to pay for her uber/lyft, which is $15 each way. which option should carla choose if she wants to spend the least? based on that choice, what then is carla's oppotunity cost? fully explain your answer in at least one paragraph.