A cistern 9m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the wet surface is: Choose the correct choice
A) 49 m2 B) 50 m2 C) 53.5 m2 D) 68.5 m2 E) 57 m2
Area of the wet surface	= [2(lb + bh + lh) - lb]   = 2(bh + lh) + lb   = [2 (4 x 1.25 + 9 x 1.25) + 9 x 4] m2   = 68.5 m2.   Answer: Option 68.5 m2
<result>D</result>
A cistern 9m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the wet surface is: