The sum of 5th and 9th terms of an AP is 30. If its 25th term is three times its 8th term, find the AP.
a5 +a9=30
(a +4d) + (a +8d)=30
2a +12d=30
a + 6d=15 (i)
Acc. To question,
a25 =3a8
a+ 24d = 3(a +7d)
3d=2a
3d=2(15 -6d) [from(i)]
15d=30
d=2
Putting the value of d in (i),
a= 15 – 6(2)=3
a1 = a=3
a2 =a +d=3 +2=5
a3 =a +2d=3 + 2(2)=7
Hence, the A.P. is 
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