((i raised the points and this is multiple choice))
which sequences are geometric ?
choose all that apply

a) 100, 90, 80, 70, 60, . .
b) 320, 80, 20, 5, 1.25, . . .
c) 4, 9, 19, 24, 34, . .
d) 1/3, 2/3, 4/3, 8/3, 16/3, . .

B and D

Step-by-step explanation:

Geometric sequences and series. A geometric sequence is a sequence of numbers that follows a pattern were the next term is found by multiplying by a constant called the common ratio, r.

an = ar^(n-1)

d) 1/3, 2/3, 4/3, 8/3, 16/3, . . . .

1/3 * 2 = 2/3

2/3 * 2 = 4/3

4/3 * 2 = 8/3

where r = 2, constant multiplier is 2.  //Answer

b)  320, 80, 20, 5, 1.25, . . . . .

320 * 1/4 = 80

80 * 1/4 = 20

20 * 1/4 = 5

r = 1/4 //Answer

B and D

//Hope this helps.

answer: the answer is one of

step-by-step explanation:   we are given to write a proper fraction where the whole is divided into an even number of equal parts less than ten, and an odd number of those parts exist.

an even number less than 10 may be one of 2, 4, 6 or 8. so, the whole may be one of these four evens.

now, an odd number of these parts must exist, so the numerator must be an odd number, one of 1, 3, 5 or 7. it cannot be 9 because then the fraction will become improper.

thus, our fraction may be one of the following

answer: check all that apply, where the options?

step-by-step explanation: