The half-life of a certain substance is 18 years. how long will it take for a sample of this substance to decay to 63% of its original amount?

It will take 12 years to decay 63% of the substance.

Step-by-step explanation:

Given information:

The half life of substance = 18 years

Now , we know that

where,

initial mass

decay constant

time

now put the values in above equation:

As:

Now for 63% decay , we can write as:

Hence, it will take 12 years to decay 63% of the substance.

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question 1 is 8, question 2 is 9, question 3 is 24

step-by-step explanation:

now, the numbers they give you at the top are the key. from there, you just have to plug and chug! let's try 1, 2, and 3!

key: a=3, b=5, c=6

1. a+5

remember, a=3, so we plug that in to get 3+5=8

2. 15-c

c=6, so we plug that in to get 15-6=9

3. 4b

b=6, so we plug it in to get 4*6=24

time to try the rest on your own! if you put the answers below in a comment, i'll check them for you!

correct answer is option b.

step-by-step explanation:

the true statement about geometric figure is option b that is one line can be drawn through all three points.

if three points are on the same plane, they can be connected by a line.