Answer:
mean life = 8264.5 s
Step-by-step explanation:
k = - 0.000121
The relation is given by

Now, the mean life is the life time for which the sample retains.
The mean life is the reciprocal of the decay constant.
The relation between the mean life and the decay constant is

Answer: B.), D.), and E.)
Step-by-step explanation:
That’s the answer on USAtestprep
Answer:
10 kph
Step-by-step explanation:
Find the speed of the current of the river.
20/(20 - c) + 180/(20 + c) = 8
20(20 + c) + 180(20 - c) = 8(400 - c^2)
8c^2 - 160c + 800 = 0
8(c^2 - 20c + 100) = 0
8(c - 10)^2 = 0
c = 10
The speed of the current of the river is 10 km/hour.
Answer:
1668.75
Step-by-step explanation:
Abu X + 5
Razak 2x + 10
Ahmad X
Together 4x + 15
175 - 15 = 160
160 / 4 = 40
X = 40