The fifth term of an A.P is 24 and the eleventh term is 96. Find the first term.
-
A.
12 -
B.
4 -
C.
-12 -
D.
-24
Correct Answer: Option D
Explanation
U5 = 24, n = 5 and U11 = 96, n = 11
Un = a + (n-1)d
24 = a + (5-1)d imply 24 = a+4d …..eqn1
96 = a + (11-1)d imply 96 = a+10d …eqn2
eqn1 – eqn2 -72 = -6d
d = 72/6 = 12
but 24 = a+4d
24 = a + 4(12)
24 = a + 48
a = 24-48
a = -24