The 3rd term of arthmetic sequence is 3/4th of 6th term.and their sum is 60.find a,d and nth term.

Answer 1

a + 2 d = (3/4)[ a + 5d ]
and
2 a + 7 d = 60

------------------------
(1/4 a -7/4 d = 0
or
1 a - 7 d = 0
2 a + 7 d = 60
------------------- add
3 a = 60
a = 20
d = 20/7

an = 20 + (n-1)(20/7)