<PRE><B>Question 1024273</B>
Mr Li travel by taxis or bus to work
Distance is 25 km and the speed of taxis is v km/hr
The taxis travel 20 km/hr faster than the bus
--------
Time for the taxi = 25/v hours.
---
Time for the bus = 25/(v - 20) hours.
---
25/(v-20) - 25/v = 0.25 hours
100/(v-20) - 100/v = 1
100v - 100(v-20) = v(v-20)
100v -100v + 2000 = v^2 - 20v
v^2 - 20v - 2000 = 0
----
*[invoke solve_quadratic_equation 1,-20,-2000]
================
v =~ 55.8 km/hr (taxi)
v - 20 =~ 35.8 km/hr (bus)</PRE>