Can someone please check this radiochemistry question please

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SUMMARY

The calculation of the half-life of sodium pertechnetate was performed using the decay formula A = A0 e^-λt. Initial activity was measured at 51439 counts per minute (cpm), and after 8 hours, it decreased to 20476 cpm. The decay constant (λ) was calculated to be approximately 0.1144, leading to a half-life of 6.02 hours. The final answer confirms the accuracy of the calculations and algebra involved in determining the half-life.

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Homework Statement



A sample of sodium pertechnetate injection was found to have an activity of 51439 counts per minute (cpm). The sample was measured again exactly after 8 hours and found to have an activity of 20476 cpm. Calculate the half life of sodium pertechnatate.

Homework Equations



A = A0 e^-lamdat
ln A = in A0 - lamdat
half life = ln2/lamda

The Attempt at a Solution



ln 20476 = ln 51439 -lamda * 8
9.927008748 = 10.84815192 - lamda * 8
0.9150875487/8 = -lamda
lamda = 0.1143859436

half life = 6.06 hours

Is this correct? I think I did the algebra a bit wrong but the answer of 6 hours sounds about right... can anyone help please...thanks.
 
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Okay I went wrong... I now get the answer of 6.02 hours...
 

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