The time it took her to drive 2 km is 11.43 seconds, because sonverting kilometers to meters, it is 1000 meters to every kilometer, and she travels 2 kilometers, which is two-thousand meters. Then to find the time you need to divide the time by the speed, and with that you get 11.4285714286, or 11.43 seconds.
Answer:
After 2 half-lives there will be 25% of the original isotope, and 75% of the decay product. After 3 half-lives there will be 12.5% of the original isotope, and 87.5% of the decay product. After 4 half-lives there will be 6.25% of the original isotope, and 93.75% of the decay product.
Explanation:
Double replacement because H and K are both switching