Answer :
Stefan take 17 hours and Jaidee 18hours ,time taken by both of them if they work together is equal to 8.74 hours.
As given,
Time taken by Stefan 17 hours
work in 1 hour = 1/ 17
Time taken by Jaidee = 18 hours
work in 1 hour = 1/18
If worked together:
Work complete in 1 hour = (1/17) + (1/18)
= 35 / (17)(18)
Time taken to complete 1 work= (17)(18) /35
= 8.74 hours
Therefore, ,time taken by both of them if they work together is equal to 8.74 hours.
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