Question 329349
in the 3 days they worked together , they completed 2/3 of the job (3 / 4 1/2)


so the son took 6 days to do 1/3 of the job ___ it would take him 18 days to do the job by himself


in 4 1/2 days , the son does 1/4 of the job (4 1/2 / 18)


so Dave does 3/4 of the job in 4 1/2 days ___ it would take him 6 days to do the job by himself (4 1/2 / 3/4)