Hi guys can someone help me with these 2 question?

1. Suppose the original size of a user message is 90 bytes and each of the three layers add a header of 20 bytes to the data. What percentage of the message being transmitted is not part of the original user message?

2. If the throughput (i.e., data rate) of a connection between hosts A and B is 4Mbps, the distance between them is 600 km, and the propagation delay between them is 6 microsec/km. How many microseconds does it take to transmit 1000 bytes from A to B?

Thank you in advance guys.