From the statement you can find the function that represents the percent of strontium-90 that remains after t years of the nuclear accident.
Call P the percent:
---> P = e ^ (- 0.025t)
Now you can also estimate the half-life of the isotope strontium-90:
Call Pi the initial percent and P2 the half percent:
P2 = 0.5 * P initial =>
P2 = 0.5 * Pinitial = Pinitial * e ^ (-0.025 t)
=> 0.5 = e ^ (-0.025t)
=> ln 0.5 = -0.025t
=> t = - ln (0.5) / 0.025
=> t = 27.7 years <----- half-time
Answer:
.205
Step-by-step explanation:
Answer:
For the extra credit question just plant the dotss and if its a square then do what it sais
Step-by-step explanation:
<span>3 black ribbons and 12 green ribbons
so P(</span><span>Lila selects a black ribbon)=3/(3+12)
=1/5
</span>2 black ribbons and 12 green ribbons left
P(<span>Jessica selects a green ribbon)=12/(12+2)
</span>=6/7
so P(<span>Lila selects a black ribbon and Jessica selects a green ribbon)
</span>=1/5*6/7
=6/35
ans is D