Answer:
Step-by-step explanation:
Decay of carbon - 14 is exponential in nature . It decays as follows .
λ is called decay constant .
λ = .693 / T where T is half life .
Half life of carbon-14 is 5700 years
λ = .693 / T
= .693 / 5700
= 12.158 x 10⁻⁵ year⁻¹
N = .71 N₀
Taking ln on both sides
ln .71 = - λ t
ln .71 = - 12.158 x 10⁻⁵ t
-0.3425 = - 12.158 x 10⁻⁵ t
t = .3425 / 12.158 x 10⁻⁵
2817 years .
80% converted to a decimal is 80/100=0.8
Multiply the total with the percent 685*0.80
The answer is 540
Answer:
E
Step-by-step explanation:
let a, b, c represent the number of students in 6th, 7th, 8th grade
ratio of students : teachers = 28 : 1
There are 82 teachers , so 28 × 82 = 2296 students
Then
a + b + c = 2296 , that is
828 + b + c = 2296 ( subtract 828 from both sides )
b + c = 1468 → E
