Question

The difference between 7th term and 2nd term is 20.Find the common difference?​

Answer 1

Answer:

7th term=a7=a+6d

2nd term=a2=a+d

a7-a2=a+6d-(a+d)

=a+6d-a-d

=5d

therefore 5d=20

d=20/5=4

d=4

Answer 2

Given

• Difference between 7th term and 2nd term is 20

To Find

• Common difference

Solution

As we know that

→ an = a + (n - 1)d

According to the question

→ a7 - a2 = 20

→ [a + (7 - 1)d] - [a + (2 - 1)d] = 20

→ [a + 6d] - [a + d] = 20

→ a + 6d - a - d = 20

→ a - a + 6d - d = 20

→ 5d = 20

→ d = 20/5

→ d = 4

Hence,

• Common difference (d) = 4

NOTE :

• an = a + (n - 1)d
• First term (a)
• Number of terms (n)
• Common difference (d)