A cistern 6m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the wet surface is:
Choices:
A) 49
B) 50
C) 53.5
D) 55
E) 57

Rationale: "explanation : area of the wet surface = [ 2 ( lb + bh + lh ) - lb ] = 2 ( bh + lh ) + lb = [ 2 ( 4 x 1.25 + 6 x 1.25 ) + 6 x 4 ] m 2 = 49 m 2 answer : a"
Answer: A