50× 25+(50× 2.5+25× 2.5 )× 2 =1625 (square meter)

8. (8× 6+8× 3+6× 3 )× 2-1.4-8× 6 =120.6 (square meter)

120.6×4=482.4 (yuan)

9,65-10 = 55 (cm)

Yellow paint: (40×55+40×65+40×40)×2=6400 (square centimeter)

Red paint: 40× 65+40×10+40× 40× 4+40× (65-40) =10400 (square centimeter).