Question

Two A.P.s have the same common difference. The
first term of one of these is – 2 and that of the
other is – 10. The difference between their 10th
terms is :
(a) 8 (b) – 8 (c) 4 (d) – 4

Answer 1

Let the common difference be d

The 10th term of 1st AP is
$- 2 + (10 - 1) \times d = 9d - 2$
The 10th term of 2nd AP is
$- 10 + (10 - 1) \times d = 9d - 10$
Therefore difference between 10th terms
$(9d - 2) - (9d - 10) = 8$
Note: If the difference of 1st is taken from 2nd, answer will be -8