Respuesta :

Answer:

  • 5

Explanation:

Let the number of half lives be x

Solve this equation to find the value of x:

  • 125*(1/2)ˣ = 3.90625
  • (0.5)ˣ = 3.90625 / 125
  • (0.5)ˣ = 0.03125
  • log (0.5)ˣ  = log 0.03125
  • x =  log 0.03125 / log 0.5
  • x = 5