Struggling with Radioactive Decay Series!

[fastjerk]

Hi everyone, I've been working on this problem for a few hours and am finally looking to get some help.

 

Considering the decay chain for U-238. For an initial activity of 1 Bq, how many Bq of U-234 exist at 10,000 years?

 

I know (U-238 -> Th-234 -> Pa-234 -> U-234)

 

 

NTh234 = (KU238/KTh234-KU238) * N0U238 (e^(-KU238*t)-e^(-KTh234*t) + N0Th234e^(-KTh234*T)

 

 

NPa234 = (KTh234/KPa234 * KTh234) * N0Th234 (e^(-KTh234*t) - e^(-KPa234*t)) + N0Pa234*e^(-KPa234*T)

 

 

NU234 = (KPa234/KU234-KPa234)*N0Pa234(e^(-KPa234*T) - e^(-KU234*t)) + N0U234e^(-KU234*t)

 

 

K = Decay Constant

 

T = time (10,000 years)

 

I have the half life, and decay constant, but I'm not sure about the N0 term.

Help please