9.25%
3.70/40= 0.0925
0.0925x100= 9.25%
We can determine this to be a Geometric Sequence with:
a = 2
r = 1/2
an = ?
We must first find an. We know that an = 1/256, therefore we can use this formula to discover an:
an = a * r^n-1
1/256 = 2 * 1/2^n-1
<span>1/256 / 2 = 1/2^n-1
</span>1/512 = 1/2^n-1
<span>log(1/512) = log(1/2^n-1)
</span>9 = n - 1
10 = n
Therefore, we know an = 10
Now we input it into this equation and solve:
Sn = a(1-r^n/1-<span>r)
</span>Sn = 2(1-1/2^10/1-1/2<span>)
</span>Sn = 2(1023/1024 / 1 / 2)
Sn = 2(1023/1024 * 2 / 1)
<span>Sn = 2(2046/1024)
</span><span>Sn = 2(1023/512)
</span>Sn = 1023/256
Sn = 3.992
Geez, that took awhile... xD
5
7
X3.8
26.6
So you multiply 7x8 and you get 56 then you put the 6 down and carry the 5 and then you multiply the 3x7 and you get 21 but you add the 5+21 and get 26 then you put the decimal after one number because that is how it is in 3.8