physics grade 10, very basic help!?

[Alexander F]

1. They are approximately 325 m apart.

2. They will collide at approximately 1.9 seconds.

3. Romanella's speed would be the same; 2 m/s.

[itsgoingtobealright]

1. Michelle and Andrew live 1 200 m apart. They decide to walk towards each other. If Michelle walks 2.2 m/s and Andrew wants 2.8 m/s at what distance would they be apart after 3 minutes.
- My answer for this was 300 m .. i dont know if its right

2. Two planes are flying towards each other at a speed of 240 m/s. At the begnning, the planes are 910 m apart. If the pilots go the same speed the whole time, how long can they go towards each other before causing a collision.
- I got 1.9 seconds.. again i'm not sure if this is right

3. Concette and Romanella live on Sumerhill, 850 m a part. They have a meeting point 330m from the two houses. Concette who has to walk the longest distance walks at the speed of 2 m/s. If Romanella leaves at the same time, what would her speed have to be to arrive at the same time as Concetta.
- I have no idea how to do this one so any help would be appreciated thanks