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.
<span>Half-span is half of span. Pitch of the roof is calculated as rise/(span/2). In this case, rise is 8 feet and span is 30 feet. So, the pitch can be calculated as 8/(30/2) or 8/15. Pitch is normally represented as the number of inches of rise per foot. So, to reduce 8/15 to match a foot, we multiply it by 12. So, (8/15) * 12 gives us 6.4 inches of rise per foot.</span>
You can change 24.5% by moving the decimal point
24.5%=.245
70,000 x .245=$17,150
64
-------------------------------
Answer:
8016
Step-by-step explanation:
28,000 x 0.92^15 = 8016.327314
