Answer:
Ratio of parent to daughter nuclei is 16 : 1
OR
1 : 0.0625
Step-by-step explanation:
The half of a radioisotope is the time it will take half of the original mass to decay.
Let the original mass be y
After the first half life, the new mass will be y/2
After the second half decay, the new mass will be y/4
After the third half decay, the new mass will be y/8
After the fourth half life decay, the new mass will be y/16.
Thus the ratio of the mother nucleus to the daughter nucleus will be y : y/16
Multiply the ratio through by 16
= 16y : y
= 16 : 1