The "k" value should have units and should be negative.
k = -.07 / seconds
Half-Life = ln (.5) / k
Half-Life = ln (.5) / -.07
Half-Life = -.693147 / -.07
Half-Life = 9.9 seconds
(actually, wkpedia says half-life of Krypton 91 is 8.57 seconds)
elapsed time = half-life * log (bgng amt / end amt) / log (2)
elapsed time = 9.9 * log (100 / 10) / 0.30102999566
elapsed time = 9.9 * 1 / 0.30102999566
<span><span>elapsed time = 9.9 * 3.3219280949
</span>
</span><span><span><span>elapsed time = 32.8870881395
</span>
</span>
</span>
<span>elapsed time = 32.89 seconds (rounded)
Source:
http://www.1728.org/halflife.htm
</span>
Answer:
Step-by-step explanation:
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No solution
This will help I hope
Answer:
0.15 miles per minute
Step-by-step explanation:
You want the rate 4.5 miles in 30 minutes expressed in terms of miles per minute.
<h3>Unit rate</h3>
To find miles per minute, divide miles by minutes.
speed = miles/minutes = (4.5 mi)/(30 min) = 0.15 mi/min
Samantha can walk 0.15 miles per minute.
