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?

Paul receives 2 portions, which equals to 7.9 * 2 = 15.8

Colin receives 3 portions , this equals to 7.9 * 3 = 23.7

the difference between the 2 portions is 23.7 - 15.8  = 7.9 

hence, Colin receives £7.9 over Paul

answer: a.   one is a factor of every whole number since every number is divisible by itself.

sample answer: you can determine whether each element of the domain is paired with exactly one element of the range. for example, if given a graph, you could use the vertical line test; if a vertical line intersects the graph more than once, then the relation that the graph represents is not a function.