let's firstly convert it to an improper fraction.

Answer:
270 s
Step-by-step explanation:
4 minutes = 240s
add the other 30s
boom
100 centimeters is equal a meter so you can say 345 centimetres is the same as 3,45 metres
i hope i helped you somehow
-----------------------------
The Answer is <u><em>7.88</em></u>
-----------------------------