A work is done by three-person A, B and C. A alone takes 10 hours to complete a single product but B and C working together takes 4 hours, for the completion of the same product. If all of them worked together and completed 14 products, then how many hours have they worked?
20 hrs.
28 hrs.
40 hrs.
54 hrs.
Explanation:
A=10 and 1B+1C=14 (Given)
=> 1A+1B+1C=14+110=720
In 20 hours, working together they will complete 7 products.
Thus, in 40 hours they will complete 14 products.