Calculate a10 if a4 = 19, a1 = 10, a1 and a4 being the terms of A. P.

a4 = 19, a1 = 10 to find a10 of the
AP.

Solution:

For an
Arithmetic progression, the rth term ar = a1+(r-1)d, where d  is the common difference.
So,

a4  - a1 = a1+3d-a1 =
3d

Here a4 -a1 = 19- 10 = 9

3d
=9

d =3.

S0 a10 = a1+(10-1)d =
10 +(10-1)*3 = 37