[tex] \frac{1}{3} + \frac{1}{5} + \frac{1}{4} = \frac{20}{60} + \frac{12}{60} + \frac{15}{60} = \frac{47}{60} [/tex]
Zatem zostało mu
[tex] \frac{60}{60} - \frac{47}{60} = \frac{13}{60} [/tex]
