Answer:
Step-by-step explanation:
As an example, iodine-131 is a radioisotope with a half-life of 8 days. It decays by beta particle emission into xenon-131. After eight days have passed, half of the atoms of any sample of iodine-131 will have decayed, and the sample will now be 50% iodine-131 and 50% xenon-131.
50 grams to 25 grams is one half-life. 25 grams to 12.5 grams is another half-life. So, for 50 grams to decay to 12.5 grams, two half-lives, which would take 36 days total, would need to pass. This means each half-life for element X is 18 days.
For this case, what you should do is calculate the surface area of the figure.
We have then:
Triangles:
A1 = (1/2) * (7) * (12)
A1 = 42 in ^ 2
Rectangles:
A2 = (1) * (12.5)
A2 = 12.5 in ^ 2
A3 = (1) * (7)
A3 = 7 in ^ 2
Finally, the total surface area is:
A = 2A1 + 2A2 + A3
Substituting values:
A = 2 (42) + 2 (12.5) + (7)
A = 84 + 25 + 7
A = 116 in ^ 2
Answer:
the amount of cardboard needed to make a box for a single slice of pizza is:
A = 116 in ^ 2
The answer is 3 because if you were to round 2.9 the next whole up from that is 3
12 bags of mixed nuts for R2 each and 10 bags of dried fruit for R3 each
