Five men and nine women can do a piece of work in 10 days. Six men and twelve women can do the same work in 8 days. In how many days can three men and three women do the work?	Choose one
A) 80 days	B) 70 days	C) 20 days	D) 10 days	E) 30 days
C   20 days   (5m + 9w)10 = (6m + 12w)8   =&gt; 50m + 90w = 48w + 96 w =&gt; 2m = 6w =&gt; 1m = 3w 5m + 9w = 5m + 3m = 8m   8 men can do the work in 10 days.   3m +3w 5  + 3= 
<gadget id="calculator">5  + 3</gadget>
<output>8</output>
8m   8 men can do the work in 10 days.   3m +3w= 3m + 1w = 4m   So, 4 men can do the work in (10 * 8)/4 3  + 1= 
<gadget id="calculator">3  + 1</gadget>
<output>4</output>
4m   So, 4 men can do the work in (10 * 8)/4= 
<gadget id="calculator">(10 * 8)/4</gadget>
<output>20</output>
20 days.
<result>C</result>
Five men and nine women can do a piece of work in 10 days. Six men and twelve women can do the same work in 8 days. In how many days can three men and three women do the work?