Answer: 693 years
Step-by-step explanation:
Expression for rate law for first order kinetics is given by:

k = rate constant
t = time taken for decomposition = 1
= Initial amount of the reactant
= amount of the reactant left =



for half life : 

Putting in the values , we get


Thus half life of this isotope, to the nearest year is 693.
This value is very different from the other values
Answer:
The expression would give the probability that one marble is yellow and the other marble is red is,

Step-by-step explanation:
A bag contains eight yellow marbles, nine green marbles, three purple marbles, and five red marbles. So in total there are 25 marbles.
Hence,
Probability of getting yellow ball = 
Probability of getting red ball = 
Probability that one marble is yellow and the other marble is red is,

The 1's value in that math problem is number 4 it is right before the decimal.