Radioactive decay linked with uncertainty

[zeebujha]

PLEASE help me do this question:
M/J 2009 Physics Paper 4 q:9(b). Couldn't figure out the heads or tails of this question

http://www.xtremepapers.me/CIE/Internat ... 9_qp_4.pdf

 

[zeebujha]

anyone????????????????// :%)