Question

Which of the following is the arithmetic sequence formula for this list?
16, 31, 46, 61, ...
A. tn = 15n - 1
B. tn = 16n + 31
C. tn = n + 16

Answer 1

What's the first term?

Answer 2

Not sure :/

Answer 3

It's just the left most term in that list

Answer 4

16

Answer 5

Good, now what's the common difference?

Answer 6

I dont know :(

Answer 7

Pick any term you want (except for the first one). Which term did you pick?

Answer 8

31 i guess

Answer 9

Now subtract off the previous term from it

So

31 - 16 = ?

Answer 10

15

Answer 11

Good

Answer 12

So the common difference is 15.

Answer 13

The nth term is

nth term = (first term) + (n-1)*(common difference)

or

tn = t1 + (n-1)*d

where tn is the nth term, t1 is the first term, and d is the common difference

Answer 14

From here, just plug in what you found

tn = t1 + (n-1)*d

tn = 16 + (n-1)*15

and simplify

Answer 15

Well it say's 15m +1
But that's not an option

Answer 16

n*

Answer 17

hmm interesting, so there are only three options?

Answer 18

Yes :/

Answer 19

tn = 15n + 1 is the answer

Answer 20

that's not an option, what do i do?

Answer 21

ask your teacher about it, that's about all you can do really

Answer 22

for now, just pick any other option (the options you listed are wrong, but oh well)

Answer 23

I checked with my teacher and she said that the answer is listed

Answer 24

well there must be a typo with the problem then

Answer 25

What would be your best guess on the answer? This is my last test of the day and im trying to get it done so it can be SUMMER :D

Answer 26

tn = 15n - 1 is the closest you get, but that -1 should be a +1

Answer 27

So maybe the typo is there

Answer 28

Alright, ill try that, thanks!

Answer 29

sure thing