Answer:
126 tiles
Step-by-step explanation:
The while tiles are 3/4 of a foot (or 9 inches) x 9 in, so their area is 81 sq in. There are 14 blue tiles, so 14 x 81 = 1134 sq inches that need to be covered.
Each tiles is 3 x 3, so its area is 9 sq in. 1134 / 9 = 126 tiles
Answer: t-half = ln(2) / λ ≈ 0.693 / λExplanation:The question is incomplete, so I did some research and found the complete question in internet.
The complete question is:
Suppose a radioactive sample initially contains
N0unstable nuclei. These nuclei will decay into stable
nuclei, and as they do, the number of unstable nuclei that remain,
N(t), will decrease with time. Although there is
no way for us to predict exactly when any one nucleus will decay,
we can write down an expression for the total number of unstable
nuclei that remain after a time t:
N(t)=No e−λt,
where λ is known as the decay constant. Note
that at t=0, N(t)=No, the
original number of unstable nuclei. N(t)
decreases exponentially with time, and as t approaches
infinity, the number of unstable nuclei that remain approaches
zero.
Part (A) Since at t=0,
N(t)=No, and at t=∞,
N(t)=0, there must be some time between zero and
infinity at which exactly half of the original number of nuclei
remain. Find an expression for this time, t half.
Express your answer in terms of N0 and/or
λ.
Answer:
1) Equation given:
← I used α instead of λ just for editing facility..
Where No is the initial number of nuclei.
2) Half of the initial number of nuclei:
N (t-half) = No / 2So, replace in the given equation:
3) Solving for α (remember α is λ)
αt ≈ 0.693
⇒ t = ln (2) / α ≈ 0.693 / α ← final answer when you change α for λ
8/7 each side of the expression both go up by 1
Answer:
13
Step-by-step explanation:
The question given above may be answered through the concept of ratio and proportion. The ratio of the man's weight on Earth and Mars should be equal to the ratio of the rock's weight on Earth and Mars. By letting x be the rock's mas on Earth, the equation that would best represent the situation is,
180 / 72 = x / 16
The value of x is equal to 40. Thus, the rock weighs 40 pounds on Earth.