Volume of twin sized mattress =
39* 8.75* 75 = 25593.35 cubic inch
Volume of queen sized mattress =
60* 8.75* 80 = 42000 cubic inch
To fill 25593.35 cubic inch it takes 4 minutes
To fill 1 cubic inch it will take = [tex]\frac{4}{25593.35}[/tex] minutes
So to fill 42000 cubic inch it will take = [tex]\frac{4}{25593.35} * 42000[/tex]
= 6.56 minutes.