MHB 13.3.2 What is the 50th term of the sequence

[karush]

The 3rd and 4th terms of an arithmetic sequence are 13 and 18. respectively.
What is the 50th term of the sequence!
a, 248 b. 250 c. 253 d, 258 e, 763

b the common difference is 5 so $5\cdot 50=\boxed{250}$

basically these are easy but I still seem to miss the goal posts

 

[topsquark]

Okay, so d = 5. What is the first term in the series? What is the equation to get the nth term of the series?

-Dan

 

[Kansas Boy]

Since this has been here a while and, as topsquark implied, Karush's answer is wrong:
An "arithmetic sequence" has the form a, a+ r, a+ 2r, a+ 3r, a+ 4r ..., with "common difference" between two successive terms r. The general term is "a+ (n-1)r", NOT "nr".

Here two successive terms are 13 and 18 so the "common difference" is 18- 13= 5 as Karush said. But 13= 3+ 2(5) and 18= 3+ 3(5) so the general term is $a_n= 3+ (n-1)5$ and the 50th term is 3+ 49(5)= 248, not 250.

 

[karush]

Mahalo
yeah that post kinda got left hanging
i never found these essy