Let $P_s:= \mathbb F_2[x_1,x_2,\ldots ,x_s]$ be the graded polynomial algebra over the prime field of two elements, $\mathbb F_2$, in $s$ variables $x_1, x_2, \ldots , x_s$, each of degree $1$. We are interested in the {\it Peterson "hit" problem} of finding a minimal set of generators for $P_s$ as a graded left module over the mod-2 Steenrod algebra, $\mathscr {A}$. For $s\geqslant 5,$ it is still open.In this paper, we study the hit problem of five variables in a generic degree. By using this result, we survey Singer's conjecture for the fifth algebraic transfer in the respective degrees. This gives an efficient method to study the algebraic transfer and it is different from the ones of Singer