### If the first term of an A.P. is a and nth term is b, then its common difference is

A. $\frac{b-a}{n+1}$ B. $\frac{b-a}{n-1}$ C. $\frac{b-a}{n}$ D. $\frac{b+a}{n-1}$ Answer: Option B

### Solution(By Apex Team)

In the given A.P. First term = a and nth term = b \begin{aligned}&\therefore a+(n-1)d=b\\ &\Rightarrow(n-1)d=b-a\\ &\Rightarrow d=\frac{b-a}{n-1}\end{aligned}

A. 22
B. 25
C. 23
D. 24

A. 5
B. 6
C. 4
D. 3

A. -45
B. -55
C. -50
D. 0