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 ?

Quality Answer Required ***

Answer 1

Answer:

$1\frac{3}{5}hrs$

Step-by-step explanation:

2 men can do a work in 6 hr and 4 hr respectively .

First man worked for 2 hours .

Then the other man joined .

First man complete it in 6 hr .

So in 1 hr he does 1/6 th of the work .

In 2 hr he does 1/3 rd .

So 1 - 1/3

= 2/3 rd part is left .

Both will now do the work .

Both can do : 1/4 + 1/6

= ( 3 + 2 )/12

= 5/12 th work in 1 hour

Let the time be x .

So 5/12 × x = 2/3

= 5 x / 12 = 2 / 3

= 5 x = 2 × 4

= x = 8/5 hrs

= $1\frac{3}{5}hrs$