Which one of the following is a geometric sequence?

A. 2, –3, 9⁄2, −18⁄4
B. 0,1,2,3,...
C. 8,4,2,1,1⁄2,1⁄4,... D. –7,10,23,36,..

i think the answer is D

Can please check it ?

2 answers

Formula for a geometric sequence :

an = a1 * r ^ ( n - 1 )


an is the nth term,

a1 is the first term,

r is the common ratio.

In this case :

a = 8

r = 1 / 2

a1 = 8 * ( 1 / 2 ) ^ ( 1 - 1 )

a1 = 8 * ( 1 / 2 ) ^ 0

a1 = 8 * 1 = 8

a2 = 8 * ( 1 / 2 ) ^ ( 2 - 1 )

a2 = 8 * ( 1 / 2 ) ^ 1

a2 = 8 * 1 / 2 = 4

a3 = 8 * ( 1 / 2 ) ^ ( 3 - 1 )

a3 = 8 * ( 1 / 2 ) ^ 2

a3 = 8 * 1 / 4 = 2

a4 = 8 * ( 1 / 2 ) ^ ( 4 - 1 )

a4 = 8 * ( 1 / 2 ) ^ 3

a4 = 8 * 1 / 8 = 1

a5 = 8 * ( 1 / 2 ) ^ ( 5 - 1 )

a5 = 8 * ( 1 / 2 ) ^ 4

a5 = 8 * 1 / 16 = 1 / 2

a6 = 8 * ( 1 / 2 ) ^ ( 6 - 1 )

a6 = 8 * ( 1 / 2 ) ^ 5

a6 = 8 * 1 / 32 = 1 / 4
An employee makes an hourly rate plus any tips they earn. This tip employee made a total of $400 by working 28 hours last week. If $253 of their total earnings was their tips, what is their hourly rate of pay?
a.
$5.25
b.
$5.61
c.
$8.82
d.
$9.04