###
**For an A.P. if $\mathbf{a}_{\mathbf{2 5}}-\mathbf{a _ { 2 0 }}$ = 45, then d equals to:**

A. 9
B. -9
C. 18
D. 23
**Answer: Option A**

## Show Answer

Solution(By Apex Team)

$\begin{array}{l}a_n=a+(n-1)\times d\\
\Rightarrow a_{25}=a+24d\\
\text{ and }a_{20}=a+19d\\
a_{25}-a_{20}=45\\
\Rightarrow a+24d-a-19d=45\\
\Rightarrow5d=45\\
\Rightarrow d=9\end{array}$

## Related Questions On Progressions

### How many terms are there in 20, 25, 30 . . . . . . 140?

A. 22B. 25

C. 23

D. 24

### Find the first term of an AP whose 8th and 12th terms are respectively 39 and 59.

A. 5B. 6

C. 4

D. 3

### Find the 15th term of the sequence 20, 15, 10 . . .

A. -45B. -55

C. -50

D. 0

### The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is

A. 600B. 765

C. 640

D. 680