Two small cars same weight travel towards each other red going 2.13 seconds/meter and blue going 2.99 seconds/meter at how many meters will they collide if one starts at 0 meters and one starts at 3.5 meters.
I'll assume you mean m/s, not s/m.
Combined speed is 5.12 m/s, so they meet at
3.5 * 2.13/5.12 meters from where the red car started.