Question

What is the common difference of an

a.p. in which a21  a 7 = 84 ?

Answer 1

A 21 = 10
A 7 = 84
A = 12 let it be x and then
Ap = a + ( n-1 )d
Ap = 10 /21 + 11d
200 = 231 d
Thus d = 200/231

Answer 2

Answer:

Step-by-step explanation:

A 21 = 10

A 7 = 84

A = 12 let it be x and then

Ap = a + ( n-1 )d

Ap = 10 /21 + 11d

200 = 231 d

Thus d = 200/231