Question 890987
A man drives from Ibadan to Oyo, a distance of 48km, in 45 minutes. If he drives at 72km/h where the surface is good and 48km/h where it is bad, find the number of kilometres of good surface.
***
let x=length of good surface (distance)
48-x=length of bad surface (distance)
travel time=distance/speed
..
{{{x/72+(48-x)/48=45/60}}}
{{{x/72+(48-x)/48=3/4}}}
lcd:288
4x+6(48-x)=216
4x-288-6x=216
2x=72
x=36
48-36=12
number of kilometres of good surface=36