Q18 of 49 Page 105

The sum of the 4th and 8th terms of an AP is 24 and the sum of the 6th and 10th terms is44. Find the first three terms of the AP.

Given, a8 + a4 = 24 and a10 + a6 = 44


a8 = a + 7d


a4 = a + 3d


As per question;


a + 7d + a + 3d = 24


Or, 2a + 10d = 24


Or, a + 5d = 12 …………(1)


a10 = a + 9d


a + 9d + a + 5d = 44


2a + 14d = 44


a + 7d = 22 (2)


Subtracting equation (1) from equation (2);


a + 7d – a – 5d = 22 – 12


2d = 10


d = 5


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