Work problem in mathematics.. :)?

Question

don, ric and mike were in a committee to build a float for the homecoming parade. each of them thought that he could build it alone in 16 hours. don started work at 8:00 am, ric at 8:30 am and mike at 9:00 am. wha time did they finish the float?

Answer 1

1 : 49 ~ 1: 50 pm

Answer 2

They all work at the same pace = 1 float/16 hours

don works x + 1/2 hours

ric works x hours

mike works x - 1/2 hours

(1/16)*(x+1/2) + (1/16)*(x) + (1/16)*(x - 1/2) = 1

x/16 + 1/32 + x/16 + x/16 - 1/32 = 1

3x/16 = 1

x = 16/3 = 5 hours and 20 minutes

They finish at 8:30 + 5:20 = 1:50 pm

Answer 3

12:54?

Answer 4

1:59 pm

how ??

when don starts at 8 he does 1/16th of the work till 9 and ric does 1/32 of the work from 8:30 to 9 so till 9,  3/32 of the work has been done now we have to do 29/32 of the work with the rate of 3/16 as all the three are working. now using unitary method we get that it will take 4hrs and 50 min more after 9 to complete the work

hope this solved your problem

Answer 5

I'm assuming this is homework...

If we answer this you won't learn anything.  

Answer 6

work done by each in 16 hr.

work done by each in 1 hr = 1/16

work done by don from 8:00 to 9:00 = 1hr = 1/16

work done by ric from 8:30 to 9:00 = 1/2hr = 1/8

work done upto 9:00 = 1/16 + 1/8 = 3/16

work remained = 1 – 3/16 = 13/16

work done by 3 of them in 1 hr = 3/16

for 3/16 work time required = 1 hr.

so for 13/16  work time required = 13/16 × 16/3 = 13/3 hr

= 4 1/3 hr = 4 hr 20 min

so work will be completed at 9:00 + 4 hr 20 min

= 13 hr 20 min. ie. 1:20 pm

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Answer 7

If it takes them each 16 hours to finish alone, then they each get 1/16 of it done in an hour, or 1/32 done in 1/2 hour

from 8-830, Don gets 1/32 of the float done

from 830-900, Don and Ric get 2(1/32) = 2/32 of the float done

so at 9:00, 3/32 of the float is done

since 3/32 is done, there is 29/32 left to do

the three of them working together get 3/16 of the float done in an hour

(29/32) / (3/16) = 29/32 * 16/3 = 29/6 = 4 5/6 hours for the three of them working together to get the last 29/32 done

9 + 4 5/6 = 1:50 p.m.  (5/6 of an hour = 50 minutes)

Answer 8

wait, so are they working together? or are each of them trying to do it alone?  like did don start at 8:00.. then ric came to help at 8:30.. then mike @ 9? or are they all working on the same one??  this is drastically change your answer, i am hoping that they are working together, becasue this will make the problem way more fun... basically what you do is since they all can complete it at the same time, when all of them are working together they can complete it in 1/3 of 16, which is 5 hours and 20 min(about)  when only two of them are working, they can finish it in 8 hours. and when 1 alone is working he can fnish it in 16 hours.. so for the first 30 min,  he is alone, so he can get .5 / 16 of the job done. then when his friend joins 30 min later they work for 30 min, which is .5/ 8 then finally when all 3 of them are working together, they will finish it up to get the rest of the fraction together, so add all these times up, and you wil lget your answer!

Answer 9

each one can build it alone in 16h

so each one can do 1/16 job in one hour

and 1/32 of the job in half an hour

at 8:30 it is 1/32 job done

from 8:30 until 9:00 they work together  and do 2/32 of the job

at 9:00 is 3/32 job done

now they work all togheter  and can do 6/32  of the job per hour

after 4 hours they do 24/32 job

plus 3/32 ,makes 27/32

5/32 left can be done in 5/6h = 50 min

so the job will be finished at 13:50  or 1:50 pm

Answer 10

Assuming each person 'can' build it in 16 hours individually,

Don starts at 8:00 for 1/2 hour when Ric joins him.  This leaves 15 1/2 hours of work.  For two people work twice as fast so when  Mike joins at 9:00 1 hours work is done so 14 1/2  hours left between 3 people meaning it will be completed in 4 5/6 hour.  i.e. 4 hours 50 mins.

Therefore the float will be done by 13:50

Answer 11

at night 1:00 am the last mike will finish his work to complete float