In a school of 1,400 pupils, 65% come by school van. Of the pupils who do NOT come by van, 40% walk to school. What per cent of the whole school walks?

Pupils not coming by van = 100 - 65 = 35%, that is 490 of the 1,400. Of those, 40% walk: 40% of 490 = 196, and 196/1400 = 0.14 = 14%. Shortcut: $0.35\times 0.40=14$%. 26% is $0.65\times 0.40$ - the classic slip of taking the 40% on the van group rather than on its complement. 40% repeats the given rate, and 35% is the size of the non-van group itself.