Answer:
135°+97°+x=180°. 232°+x=180°. x=232-180=102°
:x=102°
So, the first thing you want to find out is how many seconds each person adds to the wait time. Find out how many seconds are in 20 minutes.. 20*60=120. 120/150=0.8 seconds. Each person adds 0.8 seconds to the wait time. Now, multiply that by 240.. 240*0.8=192 seconds. Lastly, find out how many minutes 192 seconds is... 192/60=32 minutes.
I hope I did that right! And if I did, I hope that helped!