This can be considered a speed problem. We know our general equation for speed is speed×time=distance. We can change this a little for our problem, saying that the "distance" we want to travel is 1 newspaper route. So we can say speed×time=1 for this specific scenario. We can simplify this by letting S=speed and T=time so our equation says S×T=1.
For Trent, we know he takes 60 minutes so to find his speed we use T=60 and get S×60=1. Solve this for S and we get S=1/60.
For Lois we can do the same. For her we use T=30 and get S×30=1 and find that S=1/30.
Now we need to consider if they work together. To find their speed working together we add their individual speeds. So 1/60+1/30. (You need to get a common denominator). You should end up with a combined speed of 3/60, or 1/20 simplified.
We can then plug this into our S×T=1 equation to get 1/20×T=1. Solve this for T to get the time it takes to complete 1 paper route together. You should end up with 20 minutes.
