Answer:
Number of goblins = 120
Step-by-step explanation:
Let number of goblins in the magic club be x
Number of goblins and wizards all together in the magic club are given to be 220
⇒ Number of wizards in the magic club be 220 - x
Now, according to the condition given in the problem
⇒ Number of goblins = Number of wizards + 20% of number of wizards
⇒ x = 220 - x + 20% of (220 - x)
⇒ x = 220 - x + 0.2·(220 - x)
⇒ 2·x = 220 + 44 - 0.2·x
⇒ 2.2·x = 264
⇒ x = 120