Problems-solving in Equations The distance between the two cities A and B is 300 km, set off a car from the city a toward the city b by speed 90 km/h and set off from the city b bicycle toward a by speed of 10km/h.  if you knew that the car and the bike were based in nine in the morning. Select the time that the car and the bike are going to met ?      
Equation for the 8th grade ! 
Please help i need to get a formulation of this equation 

Hint: 
$$ v = \frac{\mathrm{d} x}{\mathrm{d} t} = 100 $$
Integrating, you get a very simple equation of x. If you set x(0) = 0, the equation simplifies to remove the constant. 
Now, x = 300. Solve for t. 
