Jack and Serena can write a lab report together in 12 hours. If all people work at the same rate, how many hours would it take to write a lab report if Kay joins Jack and Serena?
P.S.
Any other solution before this is wrong.
1/J + 1/S ==1/12
But J == S
1/J + 1/J ==1/12, solve for J
J == 24 hours - time it takes Jack working alone to write the lab report
S == 24 hours - ...................Serena..........................................................
Kay ==24 hours as well:
Therefore: Jack, Serena and Kay would finish the report in:
3 / 24 ==8 hours
