Question

Two men can do a piece of work in 6 hour and 4 respectively after the first person had worked for 2 hour he is joined by the end of the by when should the work be completed?​

Answer 1

Answer:

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 = 1/4

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 x 2/3 = 8/5 hrs

Total time taken to be completed the work = 2 + 8/5 = 18/5 = (10+8)/5= 18/5

= 3 3/5 hrs = 3hr 36 min

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

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