Find the 6th term of a geometric sequence with t1=5 and r = -1/2

-5/8

-5/16

-5/32

-5/64

In this item, we are to calculated for the 6th term of the geometric sequence given the initial value and the common ratio. This can be calculated through the equation,
   
                 An = (A₀)(r)ⁿ ⁻ ¹ 
where An is the nth term, A₀ is the first term (in this item is referred to as t₀), r is the common ratio, and n is the number of terms. 

Substitute the known values to the equation,

                   An = (5)(-1/2)⁶ ⁻ ¹
                   An = -5/32

Hence, the answer to this item is the third choice, -5/32.