Answer:
We conclude that it would take 4.5 minutes to fill the full barrel.
Step-by-step explanation:
It is stated that it took 3/4 of a minute to fill a barrel 1/6 full of water.
- It means if it took 0.75 minutes to fill the 1 part out of 6 parts.
It is conditioned that the water continues at the same rate.
so
Total parts of a barrel = 6
It takes 0.75 minutes to fill the 1 part of a barrel
Thus, multiply 0.75 by 6 will determine the total time in minutes to fill all the 6 parts of a barrel (or a full barrel).
i.e.
0.75 × 6 = 4.5 minutes.
Therefore, we conclude that it would take 4.5 minutes to fill the full barrel.
Answer: 
Step-by-step explanation:
Given
Initial mass of radium is 
It decays by half every 6 years i.e. 
For radioactive decay, sample at any time is given by
Insert the values
Thus, option (b) is correct.
Answer:
12
Step-by-step explanation: 12:3=4, 4 x 2= 8
