Respuesta :

RevyBreeze

Answer:

10:30

Step-by-step explanation:

If 11:20-20 = 30 minutes= 11:00 then 11:00-30=10:30

To check,

10:30+50 = 10:80 ( 1 Hour = 60 Minutes)

80-60=20

so

11:20

Therefore they start play chess at 10:30