Answer:
Step-by-step explanation:
Given a sample M(t)
M(t) = 120 • ( 81 / 625)^t
When is the fraction of the mass decay to 3/5 of it's mass
Generally
M(t) = Mo•(k^t)
The original mass is 120
Mo = 120
So, we want to find time when it decay to 3/5 of it's original mas
M = 3/5 × 120
M = 72
Then,
M(t) = 120 • ( 81 / 625)^t
72 = 120 • ( 81 / 625)^t
72 / 120 = ( 81 / 625)^t
0.6 = ( 81 / 625)^t
Take natural logarithmic of both sides
In(0.6) = In(81/625)^t
In(0.6) = t•In(81/625)
t = In(0.6) / In(81/625)
t = In(0.6) / In(0.1296)
t = 0.25 monthly
t = ¼ monthly
Answer:
20 degrees
Step-by-step explanation:
Answer:
9/4 = 2.25 and 3/5=.6
Step-by-step explanation:
9/4 also equals 2 1/4'