One pipe can fill a tank in 20 minutes. a second pipe can fill the tank in 30 minutes. if the tank is empty, how long would be required for the two pipes operating together to fill it?
i need the rate of work (r), the time of work (t) , and the work done (w)
the equation is rt = w.
it would if i am provided a detailed explanation

(It might also have helped immensely if you had been listening
when this was being explained in class.)

The first pipe fills 1/20 of the tank each minute.
The second pipe fills 1/30 of the tank each minute.

Operating together, the two pipes fill ( 1/20 + 1/30 ) of the tank each minute.

In order to add these fractions (or any fractions), you need a common denominator.
For these particular ones, ' 60 ' is a good choice.

( 1/20 + 1/30 ) = ( 3/60 + 2/60) = 5/60 = 1/12

The rate of work is 1/12 tankful per minute .

The most sensible choice for the time is 12 minutes.

R x T = W

( 1/12 tankful per minute ) x ( 12 minutes ) = 1 full tank