For an A.P. if a25 - a20 = 45, then d equals to:
A. 9
B. -9
C. 18
D. 23
Answer: Option A
Solution (By Examveda Team)
an = a + (n - 1) × d⇒ a25 = a + 24d
and a20 = a + 19d
a25 - a20 = 45
⇒ a + 24d - a - 19d = 45
⇒ 5d = 45
⇒ d = 9
This Question Belongs to Arithmetic Ability >> Progressions
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