Study the given pattern carefully and select the number that can replace the question mark (?) in it.

15	10	5	20
27	11	8	30
45	10	15	?

Logic: 1st Column + 2nd Column - 3rd Column = 4th Column  

First Row: 15 + 10 - 5 = 25 - 5 = 20 =  20
Second Row: 27 + 11 - 8 = 38 - 8 = 30 = 30
Following this pattern for the third row: Third Row: 45 + 10 - 15 = ?
Solving this equation, we get: ? = 40​​