a cistern 10 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?	Options.
A) 45
B) 55
C) 65
D) 75
E) 85
<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">4 * (5/4)</gadget>
<output>5</output>

<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">40 + 10</gadget>
<output>50</output>

<gadget id="calculator">10 * (5/4)</gadget>
<output>25/2 = around 12.5</output>

<gadget id="calculator">2 * (25/2)</gadget>
<output>25</output>

<gadget id="calculator">50 + 25</gadget>
<output>75</output>

<result>D</result>
a cistern 10 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?
add(add(multiply(10, 4), multiply(const_2, multiply(4, add(1, divide(25, const_100))))), multiply(const_2, multiply(10, add(1, divide(25, const_100)))))
area of the wet surface = [ 2 ( lb + bh + lh ) - lb ] = 2 ( bh + lh ) + lb = [ 2 ( 4 x 1.25 + 10 x 1.25 ) + 10 x 4 ] = 75 the answer is d .