a cistern 7 m long and 5 m wide contains water up to a breadth of 1 m 40 cm . find the total area of the wet surface .
"explanation : area of the wet surface = 2 [ lb + bh + hl ] - lb = 2 [ bh + hl ] + lb = 2 [ ( 5 * 1.40 + 7 * 1.40 ) ] + 7 * 5 = 69 m square option a"
add(multiply(const_2, add(multiply(add(divide(40, const_100), 1), 5), multiply(add(divide(40, const_100), 1), 7))), multiply(5, 7))