Question

Ann entered a race which required a run of 10 km north and a bike of 120 km west. Determine her running speed if she cycled ten times faster than she ran and the total race took her four hours to complete.

Answer 1

x - running speed
10x - speed on bike

v = s/t
s - distance
t - time

t = s/v

s₁ = 10 km
s₂ = 120 km


`(10)/(x) + (120)/(10x) = 4\\\\(10)/(x) + (12)/(x) = 4\ \ //*x\\\\10 + 12 = 4x\\\\4x = 22\ \ //:4\\\\x =(22)/(4) = 5,5\ km/h`

Solution:
Running speed = 5,5 km/h