a=nr bile
a/3=bile rosii
a-a/3=2a/3
(2a/3)/4=2a/12=bile albe
a/3+2a/12+12=a
4a+2a+144=12a
6a=144
a=24
a/3=24/3=8 bile rosii
2a/12=a/6=24/6=4 bile albe
2
a=bucata mare
b=bucata mica
b=2a/3=90 ⇒ a=270/2=135
a+b=135+90=225 cm
3.
2/7+4/7=6/7 din livada ocupa merii si perii
1-6/7=7/7-6/7=1/7 din livada ocupa alti pomi