Let a produce a number and b produce a number.
A=(B+396)/3
B=(A+396)/4
Replace B=(A+396)/4 with A=(B+396)/3.
B=[(B+396)/3+396]/4
4B=B/3+ 132+396
1 1B= 1584
B= 144
So A=( 144+396)/3.
A= 180
Total = a+b+396 =180+144+396 = 720.
3。
set up
alcohol concentration
X%
300*X%+70%*500=55%*(300+500)
300X+35000=44000
X=30
The alcohol concentration is 30%