Weiming and Yi Hao started a 10-km hike at 8 a.m.
They started walking at the same speed of x km/h.
After 2 km, Weiming increased his speed by 1 km/h
and walked the remaining distance at a constant
speed of (x + 1) km/h. Yi Hao maintained his speed
of x km/h throughout the hike.
(i) Write down an expression, in terms of x, for
the time taken by Weiming to complete the
hike.
(ii) Weiming completed the hike 30 minutes earlier
than Yi Hao. Write down an equation to
represent this information and show that it
simplifies to x² + x - 16 = 0.
(iii) Solve the equation x² + x - 16 = 0. Explain why
one of the solutions must be rejected.birw
(iv) Hence, find the time when Weiming finished
the hike.