Odpowiedź:
30% + 20% + 10% = 60%
100-60=40% - plewienie
3h = 40%
1,5h = 20% / x 5
7,5h = 100% ----> F
koszenie trawy 10%
pewienie 40%
10+40= 50%
100% - 7,5h
10% - 0,75h
50% - 3,75 czyli 4h 15 minut
4h 15 minut = 255min --->. F
