Question 587206
Let the ages of Tom and Alice be x and y respectively. 

We know that Tom's age is thrice as Alice's age.
So, x = 3y --------------- (1) 

Also, we know that the sum of their ages is 54.
Therefore, 
   x + y = 54
   or 3y + y = 54 { Using equation (1) }
       4y = 54 
  or y = 54/4 = 13.5 
Plugging back the value of y in equation (1), we get:
 x = 3*13.5 = 40.5 

Hence, Tom's age is 40.5 years and Alice's age is 13.5 years 



Hope this helps~!