9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999
Объяснение:
1CH4+2O2 》CO2+2H20
20/1=x/2
x=20×2/1=40 литров