The age of Fred is 31 years old and age of Natalie is 15 years old
Solution:
Let the age of fred be "x"
Let the age of natalie be "y"
If you add Natalie's age and Fred's age, the result is 46
Therefore,
Age of Natalie + Age of Fred = 46
x + y = 46 -------- eqn 1
If you add Fred's age to 3 times Natalie's age, the result is 76
Age of Fred + 3 times the Age of Natalie = 76
x + 3y = 76 --------- eqn 2
Let us solve eqn 1 and eqn 2
From eqn 1,
x = 46 - y ----------- eqn 3
Substitute eqn 3 in eqn 2
46 - y + 3y = 76
46 + 2y = 76
2y = 76 - 46
2y = 30
y = 15
Substitute y = 15 in eqn 3
x = 46 - 15
x = 31
Thus age of Fred is 31 years old and age of Natalie is 15 years old