Boat travels 10 mi upstream and 10 mi downstream the stream is moving 1mph and the boat took 5 1/3hrs. What is the speed of boat if the stream still?

I need help ASAP!!!! PLEASE!!!

speed of boat in still water --- x mph

time upstream = 10/(x-1)
time downstream = 10/(x+1)

isn't the total time 16/3 hours ?

I am sure you can take it from here.