If 110 students play both 
The 300 that play volleyball  includes them. 
That’s mean that 190 (300-110) play only volleyball 
Also (the same) 200 play cricket, so only cricket play 90 students (200-110)
Answer: either volleyball or cricket is 
(300-110)+(200-110)  = 190+ 90 = 280
Answer: 280