Foundation
Mathematics Foundation
nth term of AP
Question
The 5th term of an AP is 20 and the sum of its 7th and 11th terms is 64. The common difference of the AP is
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Solution
T5 = 20 ⇒ a + 4d = 20. ....(i)
(T7 + T11) = 64 ⇒ (a + 6d) + (a + 10d) = 64 ⇒ a + 8d = 32. ....(ii)
On Solving (i) and (ii), we get d = 3.