(x+y)* 12.5=9750 x+y=780

(x-y)* 13=9750 x-y=750

x=765 y= 15

The windless speed of the aircraft is 765km/h, and the wind speed is15 km/h.

We use X-rays as the box body and Y-rays as the box bottom.

x+y=36

2*25x=40y

x= 16 y=20

Answer: There are 16 sheets for the box and 20 sheets for the bottom of the box.

Please adopt! Come on!