If 5 times 5th term is equal to the 6times the 6th term of an arithmetic sequence,then its 11th is?.

Answer 1

5(a+4d) = 6(a+5d)
a = -10d

T11 = a+10d = 0

check:
a=10, d=-1
10,9,8,7,6,5
5*6 = 6*5

a=-5, d=1/2

-5,-4.5,-4,-3.5,-3,-2.5
5(-3) = 6(-2.5) = -15

In both cases, T11 = 0