Question

11. Find the common difference of the A.P., if a = 100
and t20 = 176.​

Answer 1

the cd is 4

a:100

a+19d:176

100+19d:176

19d:76

d:4

Answer 2

SOLUTION:-

Given:

In Arithmetic progression a= 100 and 20th term=176.

To find:

The common difference of an A.P.

Explanation:

We have,

• First term of an A.P. is a=100.
• 20th term=176

According to the question:

We know that formula of the A.P.

nth term= an=a+(n-1)d

So,

20th term= 100+(20-1)d=176

⇒ 100+(19)d=176

⇒ 100+19d=176

⇒ 19d=176-100

⇒ 19d= 76

⇒ d= $\frac{76}{19}$

⇒ d= 4

Thus,

The common difference of an A.P. is 4.

Remark

• The nth term of A.P. is called general term.