Answer: 2 bookcases.
Step-by-step explanation:
Let be "x" the number of bookcases that the custodian will be able to repaint completly with 5 gallons of paint.
According to the data given, the custodian needs 2 gallons of paint to repaint one bookcase. Since all the bookcases are equal, you can set up the following proportion:
Now you must solve for "x" in order to find its value:
Notice that the custodian will be able to repaint 2 bookcases completely, then you can say that:
Additive Identity Property is the answer.
So 60% = 3/5
All you do is 3/5 x 10 = 30/5 and get 6
The mass of substance left after 7 days is 13.09 g
The mass of substance left, N is given by
N = N₀exp(-λt) where λ = decay constant and N₀ = initial mass of substance present = 24 g and t = time
Also, λ = 0.693/t' where t' = half-life of iodine = 8 days
So, λ = 0.693/t'
λ = 0.693/8
λ = 0.086625/day
Since the mass of substance left is N = N₀exp(-λt) and we require the mass of substance after t = 7 days,
N = N₀exp(-λt)
N = 24 gexp(-0.086625/day × 7 days)
N = 24 gexp(-0.606375)
N = 24 g × 0.5453
N = 13.09 g
So, the mass of substance left after 7 days is 13.09 g
Learn more about radioactive decay here:
brainly.com/question/23705307
If we multiply and then divide the number by the same thing,
we won't change its value.
Take the number: 58,000,000,000
Divide it by 10¹⁰ : 5.8
Multiply it by 10¹⁰ : 5.8 x 10¹⁰
They want a single digit, so we'll round the 5.8
to the nearest whole number:
6 x 10¹⁰ .
