Question

If the third term of an ap is 12 and 10th term of an ap is 26 then it's 20 term is

Answer 1

Step-by-step explanation:

the third term =x+2d=12

the tenth term =x+9d=26

by solving this we get x and d values

substract both

$x + 2d - x - 9d = 12 - 26 \\ -7d = - 14 \\ d = 2$

substitute d value inequation x+2d=12 on we get

x value

$x + 2 \times 2 = 12 \\ x = 12 - 2 \times 2 \\ x = 12 - 4 \\ x = 8$

we want 20th term =x+19d

=

$8 + (19) \times 2 \\ = 8 + 38 \\ = 46$