We are given with
a1 = 2
r = 4
These are components of a geometric series. The first term is 2 and the common ratio is 4. To get the first six terms, we use the formula:
an = a1 r^(n-1)
a1 = 2 (4)^(1-1) = 2
a2 = 2 (4)^(2-1) = 8
a3 = 2 (4)^(3-1) = 32
a4 = 2 (4)^(4-1) = 128
a5 = 2 (4)^(5-1) = 512
a6 = 2 (4)^(6-1) = 2048
N*(21/100)=(700/100)
n=(700/100)/(21/100)
n=(700/100)*(100/21)
n=700/21
n=33+1/3
So <em><u>thirty three</u></em> $0.21 pencils can be purchased for $7.00.
