To find the 16th term, we will simply used the formula below:
[tex]S_n=\frac{n}{2}\lbrack a+(n-1)d\rbrack[/tex]
where a is the first term and d is the common difference
n is the number of term
From the question,
a=-5 d=-15 and n=16
substitute the values into the formula
[tex]S_{16}=\frac{16}{2}\lbrack-5+(16-1)\times-15\rbrack[/tex][tex]=8\lbrack-5+15(-15)\rbrack[/tex][tex]=8\lbrack-5-225\rbrack[/tex][tex]=8\lbrack-230\rbrack[/tex][tex]=-1840[/tex]
