1. As can be seen from the figure, there is only one black tile in the middle row, so the number of rows and columns of this layer of tiles is (77+ 1)/2=39. So the number of white tiles is 39*39-77= 1444.

If you want to finish the work as soon as possible, of course, you should choose the one with fewer working days, so you should go to team A and team B first.

1/(110+115) = 6 days.

It will be finished in six days.

A's salary is 6 *18 =10.08 million yuan.

B's salary is12 * 6 = 720,000 yuan.