Paul, Colin and Brian are waiters. One night the restaurant earns tips totalling £71.10. They share the tips in the ratio 2:3:4. How much more does Colin get over Paul?

the ratio in which money is shared is 2:3:4
the total money to be shared is £ 71.10
Altogether the money could be divided into (2 + 3 + 4) 9 portions
1 portion comes to £ 71.10 / 9 = £ 7.9
Paul receives 2 portions, which equals to 7.9 * 2 = 15.8
Colin receives 3 portions , this equals to 7.9 * 3 = 23.7
Therefore the difference between the 2 portions is 23.7 - 15.8  = 7.9 
hence, Colin receives £7.9 over Paul