Question

Two men can do a piece of work in 6 hours and 4 hours respectively. After the first has worked for 2 hours, he is joined by the other. By when should the work be completed ?​

Answer 1

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→ Two men can do a piece of work in 6 hours and 4 hours respectively. After the first has worked for 2 hours, he is joined by the other. By when should the work be completed ?

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→ Let the two men be A & B

→ Given :

→ A can do a piece of work in 6 hours & B can do in 4 hours .

→ A's 1 hour work = 1/6

→ B's 1 hour work = 14 Both ( A + B ) ' s 1 hour work = 1/6 + 1/4 = 5/12 = 2 + 3 ) / 12 = 5/12

→ Both ( A + B )'s 1 hour work = 5/12

→ After the first has worked for 2 hours ' he is joined by the other ,

→ ( A ) ' s 2 hour work = 2 ( 1/6 ) = 2 / 6 = 1/3

→ Remaining work = 1-1 / 3 = ( 3-1 ) / 3 = 2/3

→ 5/12 work is done by ( A + B ) in 1 hrs

→ 2/3 work is done by ( A + B ) in 12/5 2/3 = 8/5 hrs

→ Total time taken to be completed the

work = 2 + 8/5 = 18/5 = ( 10 + 8 ) / 5 = 18/5 - 3 35 hrs = 3hr 36 min

→ Hence , the Total time taken to be completed the work = 3 3 / 5 = 3 hrs 36 min .