<PRE><B>Question 850133</B>
 a + 4d+ a +7d=30,
2a+11d=30,
 a + 24d=3*(a + 8d)
a + 24d=3a + 24d

a = 0,   d = 30/11
an=(n-1)*(30/11)

a5=(4)*(30/11)=120/11
a8=(7)*(30/11)=210/11
a9=8*30/11=240/11
a25=24*30/11=720/11



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