A cistern 12 meters long and 4 meters wide contains water up to a depth of 1 meter 25 cm. What is the total area of the wet surface? Select.
A) 64  B) 72  C) 80  D) 88  E) 96
Area of the wet surface = [2(lb + bh + lh) - lb]   = 2(bh + lh) + lb   = [2 (4 x 1.25 + 12 x 1.25) + 12 x 4]   = 88   The answer is 88.
<result>D</result>
A cistern 12 meters long and 4 meters wide contains water up to a depth of 1 meter 25 cm. What is the total area of the wet surface?