John can clear a lot in 1.5 hours. His partner can do the same job in 4.5 hours. How long will it take them to clear the lot working together?

1 hour and 7.5 minutes

Step-by-step explanation:

We have the following information:

Jose makes 1 / 1.5 of the job per hour. It is his rate of work in addition to that the partner makes 1 / 4.5 of the job per hour. It is his rate of work.

Thus:

1 / 1.5 + 1 / 4.5 = 1 / x

0.8898 = 1 / x

x = 1 / 0.8888

x = 1.125

Hence, it will take 1 hour and 7.5 minutes for them to complete the job working together.