The fourth and eighth terms of an Arithmetic Progression are 16 and 40 respectively. Find the common difference.
- - 6
-
6
- -2
- 2
The correct answer is: B
Explanation
T\(_n\) = a + (n - 1)d
T\(_4\) = a + 3d = 16 - - - - - - - - - - - - - - (i)
T\(_8\) = a + 7d = 40 - - - - - - - - - - - - - - -(ii)
Solving simultaneously using the elimination method(subtract eqn (i) from eqn(ii)
4d = 24
d = \(\frac{24}{4}\) = 6
Thus, the common difference = 6.