Question 1196562
let   x = age of Shui 
   x+48 = age of Elias
    x-9 = age of Shui 9 years ago
 x+48-9 = age of Elias 9 years ago

Equation
x+48-9 = 3(x-9)

x + 39 = 3x - 27
 39+27 = 3x - x
    2x = 66
     x = 66/2 = 33
So Elias is 33 + 48 = 81

Answer
Elias is 81 years old.