There are 150 men, women and children on a plane. For every 7 men there are 2 women, and for every 1 woman there are 3 children. How many men are on the plane?

This question involves ratios; men : women = 7:2; women : children = 1:3. We need to find a common number to combine the two ratios together. If we multiply the women:children ratio by 2, the ratio becomes 2:6. Now we can combine the ratios together so that we have 7:2:6 (men:women:children). There are a total of 150 passengers so to find out how many men there are, we must add the ratio numbers together (7+2+6=15) and divide the total by 150 (150/15=10) then time 10 by 7 (7 because the ratio states there are 7 men for every 2 women and 6 children) which equals 70 men on the plane.