Question

how much alcohol should be added to 20% to make it 36% of 1200 ml

Answer 1

20% of 1200=20/100×1200=240 ml

let x ml pure alcohol should be added to 240 ml to make it 36% of (1200+x)

240+x=36/100×(1200+x)

240+x=432+9x/25

hope it helps

x-9x/25=432-240=192

16x/25=192

x=192×25/16=25×12=300ml