Answer:
2,674.14 g
Step-by-step explanation:
Recall that the formula for radioactive decay is
N = N₀ e^(-λt)
where,
N is the amount left at time t
N₀ is the initial amount when t=0, (given as 42,784 g)
λ = coefficient of radioactive decay
= 0.693 ÷ Half Life
= 0.693 ÷ 18
= 0.0385
t = time elapsed (given as 72 years)
e = exponential constant ( approx 2.7183)
If we substitute these into our equation:
N = N₀ e^(-λt)
= (42,787) (2.7183)^[(-0.0385)(72)]
= (42,787) (2.7183)^(-2.7726)
= (42,787) (0.0625)
= 2,674.14 g
Answer:
He needs 5x+56 ft
Step-by-step explanation:
To find how much of fencing he needs , we find the perimeter of the given figure
All sides are equal in a square
To find perimeter of the square we add all the sides
4 sides we have for the square
one side is x, so perimeter of square = x+x+x+x= 4x
Now we find perimeter of rectangle
Opposite sides of rectangle are equal
Here for rectangle we consider only three sides
because fourth side is common for rectangle and square
So perimeter of the rectangle (with 3 sides) = 28 +x+ 28 = 56+x
Total fencing = perimeter of square + perimeter of rectangle
4x + 56 + x= 5x+56
8 x 2 + 6x + 5=0
16 + 6x + 5=0
6x+21=0
6x+21-21=0-21
6x=-21
6x/6=-21/6
x=-7/2
Given that Jordan has a new puppy and she wants to put a fence around part of her yard to cover an area of 200 square feet.
Now we have to find what dimensions (length x width) should she make the rectangular area. None of the length or width are given so there can be lots of answers.
Since area is rectangular and we know that rectangle has different value of length and width so we just need to find two factors of given area 200 square feet.
For example 20 times 10 is 200.
So the dimension of the rectangular area will be:
Length = 20 feet and width = 10 feet
Now perimeter of the rectangle is given by formula:
Perimeter = 2(length+width) = 2(20+10)=2(30)=60
Hence perimeter is 60 feet.
Answer:
And we can find the nnumber of deviations from the mean for each limit given:
So we are 3 deviation from the mean and using the empirical rule we know that within 3 deviations from the mean we have 99.7% of the values
Step-by-step explanation:
Let X the random variable that represent the amount of time it takes him to arrive, and for this case we know the distribution for X is given by:
Where 
and 
We want to find this probability:
And we can use the z score formula given by:
And we can find the nnumber of deviations from the mean for each limit given:
So we are 3 deviation from the mean and using the empirical rule we know that within 3 deviations from the mean we have 99.7% of the values
