Question 941095
Let ahmed's age be a, let the son's age be s
From first statement, a + s = 50
From second statement, a-1 = 3*(s-1)
a-1 = 3s - 3
Solving these equations
a+s = 50
a - 3s = -2
*[invoke linear_substitution "a", "s", 1, 1, 50, 1, -3, -2 ]

Therefore, Ahmed is 37 years old this year