9x^2(2x^2 + 8x) = 18x^4 + 72x^3
Answer:
170 min
Step-by-step explanation:
We know that there is a kinetics of the first order, which has the following equation:
ln ([A] t / [A] o) = -k * t
Solving for t:
t = - ln ([A] t / [A] o) / k
How we want to know is the time required with 10%, so [A] t / [A] o = 100% - 10%, that is, 90% = 0.9. We also know that k = 6.2 * (10 ^ -4)
Knowing this, we replace:
t = - ln (0.90) /6.2 * (10 ^ -4)
t = 170 min
Which means it will take 170 minutes.
1/3 of the wall is covered in stone
It will be $3.68 for each rose bush because if she bought 6 of them for $22.08 then 22.08/6=3.68
