Two men a and b working separately, can complete a task in 6 hours and 12 hours respectively. If they work instretches of one hour alternately.A beginning at 10 a.M, at what time will the entire work be completed?
Answers
Answer:
19.30 pm
Step-by-step explanation:
In 1 hour A does 18=32418=324th of the whole job and B 112=224112=224th of the whole job (common denimnator makes the following calculations easier). So in 2 hours they do 324+224=524324+224=524th of the whole job (so at this stage we know that time needed to do the whole job will be less than 5 2-hour periods or 10 hours, as 5∗524=2524>15∗524=2524>1).
Now in 8 hours (4 two hour periods) they do 4∗524=20244∗524=2024th of the whole job. Then will be A's turn and by the end of 9 hours 2024+324=23242024+324=2324th of the job will be done and 124124th will be left, which can be done by B (as it's B's turn now) in 1/2hours (30 minutes). So total time 8+1+12=9128+1+12=912, hence they will finish at 9:00AM+912=18:30PM9:00AM+912=18:30PM.