Răspuns:
2) 8 ore
6robinete .........4ore
3robinete..........x ore
x=4x6:3
x=24:3
x=8
5)
[tex](7 {}^{9} ) {}^{4} \div 7 {}^{34} - 7 \\ = 7 {}^{36} \div 7 {}^{34} - 5 \\ = 7 {}^{2} - 7 = 49 - 7 = 42[/tex]
