Form a sequence that has two arithmetic means between - 13 and 89. a. - 13, 33, 43, 89 c. - 13, 21, 55, 89 b. - 18, - 36, - 72, - 144 d. - 18, - 81, - 144

Form a sequence that has two arithmetic means between - 13 and 89. a. - 13, 33, 43, 89 c. - 13, 21, 55, 89 b. - 18, - 36, - 72, - 144 d. - 18, - 81, - 144

Solution:

Since it has to be between - 13 and 89, letter d and b are not anymore considered to be the answer.

for a:

33 - (-13) = 46=d

43-33=10=d the value for this d is different from the two sequence,

89-43=46=d

they have different value for d, thus this is not the answer!

for c:

21 - (-13) = 34=d

55-21=34=d

89-55=34=d

they have the same value for d, thus the correct answer is c. - 13, 21, 55, 89