Answer:
1. 1343 years
2. 9 hours
3. 39 years
Step-by-step explanation:
1. Given, half-life of carbon = 5730 years.
∴ λ = 0.693/half-life of carbon = 0.693/5730 = 0.000121
If N₀ = 100 then N = 85
Formula:- N = N₀*e^(-λt)
∴ 85 = 100 * e^(-0.000121t)
∴㏑(-0.85)=-0.000121t
∴ t = 1343 years
2. Given half-life of aspirin = 12 hours
λ = 0.693/12 = 0.5775
Also N₀ = 100 then 70 will disintegrate and N = 30 will remain disintegrated.
∴ 70 = 100 *e^(-0.05775t)
0.70 = e^(-0.05775t)
㏑(0.70) = -0.05775t
∴ t = 9 hours
3. The population of the birds as as A=A₀*e^(kt)
Given that the population of birds fell from 1400 from 1000, We are asked how much time it will take for the population to drop below 100, let that be x years.
The population is 1400 when f = 0, And it is 1000 when f = 5
We can write the following equation :
1400 = 1000e^(5t).
∴1400/1000 = e^(5k)
∴ k = ㏑(1.4)/5
We need to find x such that 1400/100 = e^(xk)
14 = e^(xk)
∴ x = 39 years
Answer:
B
Step-by-step explanation:
The SA of a cone is A=pi*r^2+pi*r*s
So instead of pi*5^2, it should be pi*3*5 (5 is the length of the slant).
The first term of the sequence is already given to be 3. Use this value to obtain the second term.
a2 = 2(a1)^2 = 2(3)² = 18
Use the value of the second term to get the third term through the equation,
a3 = 2(a2)² = 2(18)² = 648
Thus, the answer to this item is letter B.
X²-3x-10=0
x²-(5-2)x-10=0
x²-5x+2x-10=0
x(x-5)+2(x-5)
(x-5)(x+2)
Answer:
22
Step-by-step explanation:
The volume of a cube is given as:
Cube volume = length × length × length
Since the edges of the cube measure 3 inches, this means that the length of the cube is 3 inches, therefore:
Cube volume = 3 inches × 3 inches × 3 inches = 27 in³
The pine tree is the shape of a cone with diameter of 1.5 inches and a height (h) of 2 inches. The radius (r) = diameter / 2 = 1.5 inches / 2 = 0.75 inches.
The volume of the cone = πr²(h/3) = π × (0.75)² × (2/3) = 1.178 in³
The number of pine trees that can be made = Volume of cube / Volume of cone = 27 / 1.178 = 22.9
The number of pine trees = 22
