posted by JD Smith .
Ports A and B are 400 miles apart. One boat starts from port A for port B at 6:05 and travels with a constant speed of 12 mph. If it leaves port A at 8:20, what speed musta a second boat have to arrive at port B at the same time? Explain your reasoning.
The first boat takes 400/12 hrs, or 33 1/3 hrs.
the second boat has to get there in 33 1/3 - 2 1/4 hrs.
speed second boat: 400/time above.