it would be car d because of what the time was on the chart (i did the test and it was correct)
To find the answer, use 
, and then use the equation 
To find it's half life.
2 over 3 plus 5 equals 5 and 2 over 3
Answer:
Well, 60 (minutes in an hour) divided by 12 (from the problem) is 5, so you have to multiply that 5 by the 5 from the problem to find that the train is going 25 (5*5) mph. Just double this for two hours, and you result in 50!
Step-by-step explanation:
