Question

What is the 100th term of the arithmetic sequence? 3, 8, 13, 18, …

Answer 1

First work out the nth term then the 100th term:

the difference between the numbers is: 5
and that zero term is: -2

so the nth term is: 5n - 2

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now using the nth term we replace n with 100,
then we get: 498

the answer is the above in bold
hope it helped :)

Answer 2

The answer is B. 498

An arithmetic sequence is an ordered list of numbers where the next number is found by adding on to the last number (ex: 2,5,8,11... is a sequence where 3 is added on to find the next number).
The equation for an arithmetic sequence is
$A_{n} =A_{1} + (n-1)d$
$A_{n}$ is the "n-th" number in the sequence (ex: $A_{1}$ is the first term in the sequence)
d is the number you add (common difference) to find the next number
The first number in the sequence is 3 so $A_{1} =3$
8-3=5  , 13-8=5  , and  18-13=5  so d=5 (add 5 to get the next number)

$A_{n}=A_{1}+(n-1)d$
$A_{100}=3+(100-1)(5)$
$A_{100}=3+(99)(5)$
$A_{100}=3+495$
$A_{100}=498$

The answer is B. 498