GRE Exam Numerical Ability Arithmetic

If seven times the seventh term of an AP is equal to eleven times its eleventh term, What is the value of 18th term ?

Read Solution (Total 3)

in A.p the 1st term is a nd common difference is d
7 x t7 = 11 x t11
=> 7 x (a + 6d) = 11 x (a + 10d)
=> 7a + 42d = 11a + 110d
=> 68d = -4a
=>a = -17d
Now, t18 = a + 17d
on putting a = -17 d we get, t18 = 0
so t18 term is zero
11 years agoHelpfull: Yes(4) No(2)

7a+42d=11a+110d
68d=-4a
a=-17d
now 18th term...a+17d as nth term is a+(n-1)d
a+17d=-17d+17d=0
hence answer is 0
11 years agoHelpfull: Yes(2) No(0)
it is given that 7times seventh term is equal to 11times the 11th term so
==> 7(x +6d) = 11(x + 10d) ==> x + 17d = 0 ==>18th term is zero
11 years agoHelpfull: Yes(1) No(0)

GRE Other Question

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