Question 940619
One car travels at 30 km/h faster then another.
 While one travels 300 km the other travels 450 km.
 find their speed
:
let s = the slow car's speed
then
(s+30) = the faster car's speed
:
Speed and distance are directly related, write a proportion equation
{{{s/((s+30))}}} = {{{300/450}}}
cross multiply
450s = 300(s+30)
450s = 300s + 9000
450s - 300s = 9000
150s = 9000
s = 9000/150
s = 60 km/hr is the slow car speed
and obviously,
90 km/hr is the fast car speed
:
;
You can confirm this by finding the time of each, should be equal
300/60 = 5 hrs
450/90 = 5