On an airplane that two-thirds full, 20% of the passengers are boys, one-fourth of the passengers are women, one-eighth of the passengers are girls, and there are 68 men. How many seats are on the plane?

To get the number of seats we proceed as follows;

let the total number of seats be x;

the number of passengers is:

2/3x

the number of boys will be:

0.2*2/3x=2/15x

the number of women will be:

1/4*2/3x=1/6x

the number of girls will be:

1/8*2/3x=1/12x

the number of men will be given by:

2/3x - (2/15x+1/6x+1/12x)

=2/3x-23/60x

=17/60x

thus the number of sit on plane will be:

x / (17/60x) * 68

=240

The number of sits are 240