One person can complete a typing project in three hours , and another can complete the same project in five hours. how long will it take the two people working together to complete the project

1.875 hours

Step-by-step explanation:

The first person completes the project in 3 hours

Let's assign 1 to the project.

This means the unit rate per hour is 1/3

The second person completes the same project in 5 hours

This means the unit rate per hour is 1/3.

Their unit rates of working is additive, this means they work simultaneously. First person does not stop working for second person to start working.

Total rates = 1/3 + 1/5 = 8/15

Let t hours be the time it takes both of them

If it takes t hours to do the project together, the unit rate of working together will be 1/t

Equating both unit rates,

8/15 = 1/t

t = 15/8 = 1.875 hours

its 4 because 2 times 2 is 4, if you double the number two you get four