Urgent!!! Physics Masters!!! Answer This!!!

[Jigar]

A Car X is travelling at a steady speed of 15 m/s. It overtakes Car Y which is travelling at 10 m/s. The driver gets irritated and immediately starts to accelerate uniformly. Car Y catches up with Car X after 20sec. Draw a velocity time graph for the two cars and determine the speed of Car Y when it catches up with Car X.

Please attach the graph if possible....and please provide a explanation to your answer......

Thanks in advance....................