QCEVault

Differential equations and related rates — Question 229

Original QCE Vault practice · 6 marks

Q229 · Practice questionTechnology-activeComplex unfamiliar6 marks

QUESTION 229 (6 marks)

Two isotopes have expected counts A(t)=100e−2ktA(t)=100e^{-2kt} and B(t)=50e−ktB(t)=50e^{-kt}. B has half-life 6 hours.
a)
Find k and when the counts are equal.
[2 marks]
b)
When does combined count first reach half its initial value? Give exact time and four decimal places.
[4 marks]
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