There are 300 passengers on a plane, 7/20 of them are men, 30% are women, the rest are children. Work out the number of children.

300 x (7/20) = 300/20 x 7 = 15 x 7 = 105 = number of men on the plane.

300 x 0.3 = 90 (Or 300/10 x 3) = number of women on the plane.

105 + 90 = number of adults on the plane = 195.

300 - 195 = 105 = number of children on the plane.