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 step is to find what should be the required total of sum of Score after fourth test, to identify how much more or less she need to score in his fourth test.
Since Mean = (Sum of Scores)/number of test
using above formula we determine what is the required sum of score.
82 = (Sum of Scores)/4
⇒ 82 × 4 = 328
So in four test she should have score total as 328
So Score require in fourth test = Required Score Total - (total score in 3 tests)
= 328 - ( 72 + 97 + 82 ) = 77
So she need score of 77 to be at mean of 82 after fourth test and get qualify for the team
The probability is 50% or half or 1/2
Pretty sure the answer is 3t26tr <3
6/4 or 1 and 2/4 thats a pretty easy question
