10•1/2+(-6)(-3) Simplified in steps
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Answer:
Step-by-step explanation:
Use the half life formula
where N is the amount after decay, No is the initial amount, e is Euler's number, k is the decay constant, and t is the time in minutes. For us, the first equation looks like this:
and we will solve that for k and then use that value of k in the second equation to find time.
Begin by dividing 7 by 12 to get
Now take the natural log of both sides since the natural log and that e are inverses. The e then disappears:
Plug the left side into your calculator and then set it equal to the right side, giving us:
Divide both sides by 70 to get the k value of
k = -.00769995
Now the second equation looks like this:
where t is our only unknown now that we know k.
Begin by dividing both sides by 12 to get
and take the natural log of both sides again to eliminate the e:
Take care of the left side on your calculator to get
-1.791759469 = -.00769995t and divide both sides by -.00769995 to get
t = 232.697 minutes
How about this (see attached image):
Use the four cuts as shown in the image (red lines).
Then assemble 5 equal squares by the numbers: 1 center square and the rest are pieced together using two pieces as shown. All five together add up to the same area as original square because we use all pieces.
The way one gets a hint toward a solution is to see how an area of a square of length 1 can be split into 5 equal square areas:
which indicates we need to find a a triangle with sides 2 and 1 to get the hypotenuse of the right length. That gave rise to the cut pattern (if you look carefully, there are triangles with those side lengths).
