Question

Alone, it takes Khalil 10 hours to complete a one-hour long presentation. It takes Teddy 8 hours to complete a one-hour long
presentation. Using a rational equation, which of the following correctly calculates how long it would take them to complete a one-
hour long presentation if they worked together? (1 point)
18 hours

4.44 hours

0.225 hours

9 hours

Answer 1

To find how long it would take them to complete a one-hour long presentation together, we can use the formula:

1 / (time taken by Khalil) + 1 / (time taken by Teddy) = 1 / (total time taken together)

Let's substitute the given values into the formula:

1 / 10 + 1 / 8 = 1 / (total time taken together)

Simplifying the left side:

0.1 + 0.125 = 1 / (total time taken together)
0.225 = 1 / (total time taken together)

Now we can isolate the total time taken together by taking the reciprocal of both sides:

(total time taken together) = 1 / 0.225
(total time taken together) = 4.44 hours

Therefore, the correct answer is:
4.44 hours.