If it takes Cindy nine hours to read a book and hardy five hours to read the same book how long will it take them to read it together

Question

Word problem for algebra 

Answer 1

We can use the following equation to solve this problem:

 

Quantity= rate x time

 

In this case, the quantity is 1 (book)

There are two rates 1/5 (books per hour) for Hardy and 1/9 for Cindy

We are solving for time (t)

Plugging these values into our equation looks like this:

 

1=(1/5+1/9)t

1=(9/45+5/45)t

1=(14/45)t

 

Solving for t, we get 45/14=t

so, t =45/14 hours, which is approximately 3.2 hours