Answer :
Answer:
(b) 137
Step-by-step explanation:
An arithmetic progression (AP) is a sequence of numbers where the difference between any two consecutive terms is constant. This constant difference is called the common difference.
In this case:
The nth term of an arithmetic progression can be calculated using the following formula:
[tex]\sf t_n = a + (n - 1) \times d [/tex]
where:
- tn is the nth term of the AP
- a is the first term of the AP
- d is the common difference of the AP
- n is the number of the term
We have,
- First term (a)= -3
- The common difference (d)= 7
So, the 21st term can be calculated by substituting given value in above formula:
[tex] \begin{aligned} t_{21 } &\sf = -3 + (21 - 1) \times 7 \\\\ &\sf -3 +20\times 7 \\\\ &\sf = -3+ 140 \\\\ &\sf = 137\end{aligned} [/tex]
Therefore, the answer is (b) 137
