Question

if i can do job in 4 hours and we can do the same job in 2 hours, how long can you do the job alone?​

Answer 1

Answer:

4 hrs will be the answer according to me

Answer 2

Answer:

Method 1:

1 hr work of A = 1/5

1 hr work of B = 1/10

1 hr work of both = 1/5 + 1/10 = (10+5)/50 = 15/50=3/10

So they together can do this job in = 10/3 hours = 10/3 * 60 min = 200 min

Method 2:(Formula method)

if A can do a job in x days and B can do this job in y days then they together can do this job in = xy/(x+y) = 5*10/(5+10) = 50/15 hours = 10/3 hours

= 10/3 * 60 min = 200 min

Method 3:(LCM method)

let total work = LCM(5,10) = 10 units

1 hr work of A = 10/5 = 2 units and that of B = 10/10 = 1 unit

Hence A & B together this work in = 10/(2+1)=10/3 hours

= 10/3 * 60 min = 200 min