To start, we need to find a common denominator fraction that [tex] \frac{5}{12} [/tex] and [tex] \frac{2}{5} [/tex] could go into. This would be 60. Our fractions would be [tex] \frac{25}{60} [/tex] and [tex] \frac{24}{60} [/tex]. We add these together to get [tex] \frac{49}{60} [/tex]. To find how much still needs to be mowed, we do [tex] \frac{60}{60} - \frac{49}{60} = \frac{11}{60}[/tex]