6 and 15 have 3 as a common factor. Thus 6:15 is 2:5. The other ratios are also the same as given in the question. Since the numbers in the second column increase in 15s, the numbers in the first row should increase in sixes (12:30 is the same as 6:15 and 2:5). Thus the answers are:
- 6:15
- 12:30
- 18:45
- 24:60
- 30:75
The half life of the substance is 6.92 days.
<h3>What is the Half life ?</h3>
Half life can be defined as the time required to reduce the concentration to half of its initial value.
Here the equation given is

The concentration will reduce to half therefore

so,

ln 0.5 = - 0.1001 * t(1/2)
-0.693 = -.1001 * t(1/2)
t(1/2) = 6.92 days.
Therefore the half life of the substance is 6.92 days.
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Answer:

Step-by-step explanation:
2(4x - 8) - 10
8x - 16 - 10
|_______|
8x - 26
-5x + 8 - 11x - 12
___ ___ _____ ____
___ ____
-16x - 4
-3(4x - 5)
-12x + 15
For the third and first exercises, you just use the Distributive Property, and for the second exercise, all you are doing is combining like-terms.
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Answer:
the answer you are looking for is-10
Step-by-step explanation: