Question

The first term of an arithmetic sequence is equal to $6$ and the common difference is equal to $3$. Find a formula for the $n^{th}$ term and the value of the ${50}^{th}$ term.

• A. 151
• B. 152
• C. 153
• D. 154

Answer 1

The correct option is C 153

Use the value of the common difference $d=3$ and the first term $a_1=6$ in the formula for the $nth$ term given above.

$a_n=a_1+(n-1)d$

$=6+3(n-1)$

$=3n+3$

The ${50}^{th}$ term is found by setting $n=50$ in the above formula.

$a_{50}=3\left(50\right)+3=153$