Answer: [tex]s=\frac{1}{2}\quad \left(\mathrm{Decimal}:\quad s=0.5\right)[/tex]
Step-by-step explanation:
[tex]\frac{31}{10s}=6\frac{1}{5}[/tex]
[tex]\frac{31}{10s}=\frac{31}{5}[/tex]
[tex]31\cdot \:5=10s\cdot \:31[/tex]
[tex]155=310s[/tex]
[tex]\frac{310s}{310}=\frac{155}{310}[/tex]
[tex]s=\frac{1}{2}[/tex]