30%=0,30=0,3 0,3*1,2=0,36
70%=0,7 0,7*1,1=0,77
0,36+0,77=1,13 1,13-1=0,13=13%
(8 7/12 - 2 17/36)*2.7-4 1/3 : 0.65=289/39
8 7/12 - 2 17/36 = 103/12-89/36=309/36-89/36=220/36
2.7=2 7/10=27/10
220/36*27/10=66/4=33/3
4 1/3 : 0.65=7/3 : 65/100=7/3*100/65=700/195=140/39
33/3-140/39=429/39-140/39=289/39
14-y=19-11y
-y+11y=19 -14
10y=5
y=1/2