Radium has a half-life of 1,620 years. in how many years will a 1 kg sample of radium decay and reduce to 0.125 kg of radium?
a. 1,620 years
b. 3,240 years
c. 4,860 years
d. 6,480 years

4860 years

Explanation:

From

N/No = (1/2)^t/t1/2

Where:

No= mass as time t=0

N= mass at time t

t= time

t1/2= half life

0.125/1 = (1/2)^t/1620

1/8 = (1/2)^t/1620

(1/2)^3= (1/2)^t/1620

3= t/1620

t= 3×1620

t= 4860 years

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year

they vary. it used to be meat, grain, bread, candy, beverages, donuts, and fruits/vegetables. now they added exercise in.