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:
to solve this we do the oppisite of multiplication which is division
so 84 divided by 12 = 7 so that means that our mysterious k = 7
so reprhase the sentence so '' The product of 12 and 7 is 84
hope this helps:)
Step-by-step explanation
Answer:
2 gallons
Step-by-step explanation:
25% of 4 gallons is 1 gallons, which means that 75% of the hand sanitizer is not alcohol, and is 3 gallons. since that is the amount of not alcohol, and we want it to be 50% solution, it has to be 3 gallons of alcohol in total, and 3-1=2.
Answer:
C
Step-by-step explanation:
Convert 8 1/2 to 17/2 and this multiplied by 3 is 51/2. Convert it back to mixed fraction to get 25 1/2.
The answer to this is 5/8
