rapiddd dau coroana!!!!ex 4

2/6 din rest= 20 ==> 1/6 = 10 ==> 6/6= 60
6/7 din X, unde X =nr de nuferi, = 60
==> 1/7 = 10 ==> X= 7×10 = 70
Răspuns:
x/7 au inflorit a2a zi
⁷⁾x-x/7=6x/7 rest
6x/7·4/6=4x/7 au inflorit a3a zi
x/7+4x/7+⁷⁾20=⁷⁾x
x+4x+140=7x
140=7x-5x
x=140:2=>x=70 nuferi pe lac