(a)[1]
Write down an expression, in terms of $x$, for the time Alfredo needed to complete the race.
(b(i))[4]
Show that this leads to $2x^2 - x - 40 = 0$.
(b(ii))[4]
Use the quadratic formula to solve $2x^2 - x - 40 = 0$. Show all your working and give your answers correct to 2 decimal places.
(b(iii))[3]
Work out the time Luigi needed to complete the 10 km race. Give your answer in hours and minutes, correct to the nearest minute.