To find the percent we are looking for we can use the rule of three:
[tex]\begin{gathered} 60\rightarrow100 \\ 51\rightarrow x \end{gathered}[/tex]then:
[tex]\begin{gathered} x=\frac{51\cdot100}{60} \\ x=85 \end{gathered}[/tex]This means that 51 is 85% of 60.
Therefore 51 is 15% less than 60.