Oxford University MAT 2015 Solved Papers

Sketching the three equations suggests the answer 7 , however it is necessary to note the behaviour of the three equations when 0≤x≤1. All three equations pass through 0 , and x5>x4>x3 when x>1. When 0≤x≤1 it should be noted that x3≥slantx4≥slantx5 and that all three equations pass through (1,1). This behaviour produces two further regions (in addition to the 7 already discussed), and as such the answer is (d).