x can do a piece of work in 4 hours; y and z together can do it in 3 hours, while x and z together can do it in 2 hours. how long will y alone take to do it?
Select.
A) 5 hours	B) 10 hours	C) 12 hours	D) 24 hours	E) 15 hours
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">(1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) - (1/4)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / (1/12)</gadget>
<output>12</output>

<result>C</result>
x can do a piece of work in 4 hours; y and z together can do it in 3 hours, while x and z together can do it in 2 hours. how long will y alone take to do it?
inverse(subtract(divide(const_1, 3), subtract(divide(const_1, 2), divide(const_1, 4))))
x 1 hour ' s work = 1 / 4 ; y + z ' s hour ' s work = 1 / 3 x + y + z ' s 1 hour ' s work = 1 / 4 + 1 / 3 = 7 / 12 y ' s 1 hour ' s work = ( 7 / 12 - 1 / 2 ) = 1 / 12 . y alone will take 12 hours to do the work . c