A and B can do a piece of work in 7 days. With the help of C they finish the work in 5 days. C alone can do that piece of work in?
Answers
A) 1 day	B) 10 days	C) 30 days	D) 32 days	E) 34 days
Explanation:   30 days = 1/5 – 1/6 = 1/30 =&gt; 30 days   Answer: 30 days
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A and B can do a piece of work in 7 days. With the help of C they finish the work in 5 days. C alone can do that piece of work in?