Question

4. If 175 undecayed nuclei remain from a sample of 2800 nuclei, how many half-

lives have passed? (Show your work.) *
Your answer

Answer 1

X = 4

Step-by-step explanation:

Start 2800

End 175

175 = 2800x(0.5)^X

175/2800 = 0.5^X

0.0625 = 0.5^X

log(0.5 x) = log(0.0625)

x · log(0.5) = log(0.0625)

-0.301x = -1.204

x = -1.204/-0.301

x = 4