Answer:
From what I can see of the problem, you CANNOT solve for the half-life of U 235 AND then solve for the length of time to determine the 20% decay.
U-235 half-life is 704,000,000 years. (Wikipedia)
The elapsed time formula = half-life * [log (Beginning Amount / ending amount) / log 2]
elapsed time = 7.04 x 10^8 * [log (100 % / 80%) / log 2]
elapsed time =7.04 x 10^8 * [log (1.25) / .30103]
elapsed time =7.04 x 10^8 * [0.096910 / .30103]
elapsed time = 7.04 x 10^8 * 0.321928047
elapsed time = 226,637,000 years
Step-by-step explanation:
Answer:
(a) 0.06154
(b) 0.2389
(c) 0.6052
(d) 2478
Step-by-step explanation:
probability density function of the time to failure of an electronic component in a copier (in hours) is
P(x) = 1/1076e^−x/1076
λ = 1/1076
A) A component lasts more than 3000 hours before failure:
P(x>3000) = 1 − e^−3000/1076
= 0.06154
B) A component fails in the interval from 1000 to 2000 hours:
P(1000>x>2000) =1 − e^−2000/1076 − 1 +e^−1000/1076 = e^−1000/1076 − e^−2000/1076 = 0.3948 − 0.1559
= 0.2389
C) A component fails before 1000 hours:
P(x<1000) = 0.6052
D) The number of hours at which 10% of all components have failed:
e^−x/1076 = 0.1
= −x/1076
= ln(0.1)
x =(2.3026)×(1076)
x = 2478
Answer:
48 sq inches
Step-by-step explanation:
Given that,
Ribbon used around a bulletin broard is 28 inches
The length of her board is 6 inches
Let B is breadth of her board. 28 inches is perimeter. The perimeter of rectangle is given by :
P = 2(L+B)
28=2(6+B)
14=6+B
B=8 inches
The area of a rectangle is given by :
A = L×B
A = 8×6
A=48 sq inches
So, the area of her board is 48 sq inches
5x(8 - 4)/4 - 2
Remember to follow PEMDAS.
First, subtract 8 and 4
8 - 4 = 4
5x(4)/4 - 2
Next, follow the left -> right rule, and multiply 5x and 4
5x(4) = 20x
Divide by 4
20x/4 = 5x
Finally, note that one has a variable, and the other has a constant, and so you cannot combine.
5x - 2 is your answer
hope this helps
Given the initial rent is $40000, and the rent is increased by 0.5% each year, the rent in the third year will be given by:
FV=P(1+r)^n
FV=40000(1.05)^n
Thus the answer for the sum of payments for 3 years will be:
The summation is 1.05 raised to n years times $40000, where the years is from 0 to 3.
