The half–life of rubidium–89 is 15 minutes. If the initial mass of the isotope is 250 grams, how many grams will be left after 100 minutes?

12

step-by-step explanation:

12 + 5 = 17

12x2=24

24-7=17

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.