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>
First term = T(1) is obtained by plugging n = 1 into the formula,
thus First term = 1^2 - 4 = 1 - 4
= 3 (answer)
<span>24 cans costs £6
6/24 = 0.25 each can
5 * 0.25 = </span><span>£1.25
answer: </span>£1.25 for <span>5 cans</span>
Prime factorizations - Wednesday work
1. 44 2^2 • 11
2. 125 5^3
3. 85 5 • 17
4. 39 3 • 13
5. 63 3^2 • 7
6. 240 2^4 • 3 • 5
7. 87 3 • 29
8. 45 3^2 • 5
