Given: Out of the three number first number is thrice the second number and the third number is half of the second number. If the average of the three number is 54. Formula Used: average = sum of terms/number of terms Calculation: Let the second number be x. ⇒ first number = 3x ⇒ third number =x/2 According to question- ⇒3x+x+(x/2)=3×54 ∴ x = 36 so, first number =3x=108 ⇒ second number =x/2=18 ∴ required difference =108−18=90