10 men can complete a work in 7 days. But 10 women need 14 days to complete the same work. How many days will 5 men and 10 women need to complete the work?  Choose the correct choice from the following options.
A) 4	B) 5	C) 6	D) 7	E) 8
Work done by 10 men in 1 day = 1/7   Work done by 1 man in 1 day = (1/7)/10 = 1/70   Work done by 10 women in 1 day = 1/14   Work done by 1 woman in 1 day = 1/140   Work done by 5 men and 10 women in 1 day = 5 × (1/70) + 10 × (1/140)   = 5/70 + 10/140 = 1/7   =&gt; 5 men and 10 women can complete the work in 7 days   Answer is 7.
<result>D</result>
10 men can complete a work in 7 days. But 10 women need 14 days to complete the same work. How many days will 5 men and 10 women need to complete the work?