Question

In an arithmetic sequence, find a50 when a1=7 and d=5 a. 495 b. 252 c. 275 d. 349

Answer 1

An arithmetic sequence is an ordered list of numbers where the next number is found by adding the same amount to the number before. (2,5,8,11... is one where you add 3 to get the next number)
The equation for arithmetic sequence is
$A_{n} = A_{1} +(n-1)d$
where $A_{n}$ is the "n th" number in the sequence
($A_{1}$ is the first number in the sequence)
d is the number you add to get the next number

$A_{n} = A_{1} +(n-1)d$
$A_{50} = 7 +(50-1)(5)$
$A_{50} = 7 +(49)(5)$
$A_{50} = 7 +245$
$A_{50} =252$

The answer is B. 252