Question

John can create 3 apps in 6 weeks while Ben can do the same job in 2 weeks. How many weeks would it take them to create 10 apps together?

plzzz answer i rlly need help

Answer 1

5 weeks

Explanation:

John creates apps at the rate ...

... (3 apps)/(6 weeks) = 1/2 app/week

Ben creates apps at the rate ...

... (3 apps)/(2 weeks) = 3/2 app/week

Together, they create ...

... (1/2) app/week + (3/2) app/week = 2 app/week

So, the time for 10 apps is ...

... (10 app)/(2 app/week) = 5 week

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Comment on the problem

If the guys actually work at a uniform rate like this, the result after 5 weeks will be 9 completed apps and 2 half-completed apps. Their rate is 10 apps in 5 weeks, but their actual output in that time period may not be 10 completed apps.

One should beware of the "mythical man-month." Rates of job completion depend on many factors. Individual average rates cannot always be summed when folks "work together."