If it takes Mike and Joshua 2 hours to do a certain job, and it takes Mike and Kelvin 3 hours to do the same job, how long would it take for Mike, Joshua and Kelvin to do the job if all 3 of them worked together?
I got in a mess trying to solve this alsgebraically so I decided to takle it with an example.
Let mike and Josh both do 1/4 of the job in an hours so together they do 1/2 the job in an hour which is 1 job in 2hours.
Now Mike and Kevin together do 1/3 of a job in an hour. so 1/4 + K = 1/3 K=1/12 of a job in an hour
so together
M+J+K = 1/4 +1/4 + 1/12 = 7/12 jobs in an hour = 12/7 hours for a job = aprrox 1 hour and 43 minutes