Can someone me the 2nd problem i don’t understand it

So this means the bus B covered 390-120=270 miles when bus A has already reached 390 miles.

270 miles

Step-by-step explanation:

So is A is going faster than B so A will reach the destination first.

When will A reach it's destination?

Let's find out.

To solve this problem, the following will come in handy:

Speed=distance/time or time*Speed=distance or time=distance/speed .

time=distance/speed

So it will take bus A 6 hours to cover the distance of 390 miles.

How much time would have it taken bus B to reach that same distance?

So it would have taken bus B hours to cover a distance of 390 miles.

So the time difference is hours.

It will take more hours than bus A for bus B to complete a distance of 390 miles.

So bus B traveled miles (used the time*speed=distance) after bus A got to it's destination.

So this means the bus B covered 390-120=270 miles when bus A has already reached 390 miles.