Step-by-step explanation:
[tex] \frac{75}{100} \times x + \frac{25}{100} \times y = \frac{50}{100} \times 720[/tex]
[tex]0.75x + 0.25y = 360[/tex]
and
[tex]x + y = 720[/tex]
both volumes combined makes the last solution...
and
[tex](x + y = 720) \div 2 [/tex]
[tex]0.5x + 0.5y = 360[/tex]
now...
0.5x+0.5y=0.75x+0.25y
0.25y=0.25x
x=y
it means both volumes are same
so volume of acid must be 720/2=360mL
plug that number in to x and y
if u didnt get how i got the answer...comment me