Answer:
18 minutes
Step-by-step explanation:
A = A₀ (½)^(t / T)
where A is the final amount,
A₀ is the initial amount,
t is the time,
and T is the half life.
A = 140 when t = 10. Solve for the half life:
140 = 700 (½)^(10 / T)
0.2 = ½^(10 / T)
log 0.2 = (10 / T) log 0.5
10 / T = 2.32
T = 4.31
When A = 40, t is:
40 = 700 (½)^(t / 4.31)
0.057 = ½^(t / 4.31)
log 0.057 = (t / 4.31) log 0.5
t / 4.31 = 4.13
t = 17.8
Rounded to the nearest whole number, it takes 18 minutes.
3m + 2n= p solve for n
subtract 3m on both sides
2n = p - 3m
divide both sides by 2
n = p/2 - 3m/2
-----------------------
xy - 5 = k solve for x
add 5 on both sides
xy = k + 5
divide both sides by y
x = k/y - 5/y
Answer: The answer is A.
Step-by-step explanation:
A. 72 degrees (i hope this helped)
1.77777777778 would be the answer you are looking for I think.
