Find the 21st term of the Arithmetic Progression (A.P.): -4, -1.5, 1, 3.5,…
-
A.
43.5 -
B.
46 -
C.
48.5 -
D.
51
Correct Answer: Option B
Explanation
(T_{n} = a + (n-1)d)
( d = T_{2} – T_{1} = T_{3} – T_{2} = -1.5 – (-4) = 2.5)
(T_{21} = -4 + (21 – 1) times 2.5 = -4 + (20times 2.5) )
= (-4 + 50 = 46)