Question 1177891
4/x + 5/(x+2) = 5/6

(4x+8 +5x)/x(x+2) = 5/6

6(9x+8)= 5x(x+2)

54x+48 = 5x^2 +10x

5x^2 +10x -54x -48=0

5x^2-44x -48 =0

First 5 km Section
Distance (km) 5
Speed (km/h) x
Time (h) 5/x

Last 4 km Section
Distance (km) 4
Speed (km/h)x+2
Time (h) 4/(x+2)

5/x + 4/(x+2) = 5/6

(5x+10 +4x)/x(x+2) = 5/6

6(9x+10)= 5x(x+2)

54x+60 = 5x^2 +10x

5x^2 +10x -54x -60=0

5x^2-44x -60 =0

x=10 

Last 4 km at 12 km/h