Answer:
14
Step-by-step explanation:
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:1. the 1 one do a half base×height ( 1/2 × 9×17).
2. the second one do 15 ×18 and 20×9 then subtract the2 answers
=15×8=270 20×9=180 270-180=90.
=90
please mark me the brainlest.
The sixth grade runs a bake sale for 55 hours and makes $170.
So in one hour, they made 170/55 = 3.09 dollars.
Rate: $3.09/h
The seventh grade sets up a dunking booth for 44 hours and makes $112.
So in one hour, they made 112/44 = 2.54 dollars.
Rate: $2.54/h
The eight grade has a car wash and makes $192 in 66 hours.
So in one hour, they made 192/66 = 2.90 dollars.
Rate $2.90/h
3.09 > 2.90 > 2.54
So R(6th) > R(8th) > R(7th)
Which means that the sixth grade has the highest rate for raising money.
Hope this helps! :)
