Let's give Cindy's age a variable.
Cindy's age = x
Cindy multiplies her age by 5
x(5)
Subtracted by 12
x(5) - 12
Divide by 3
(5x - 12)/3
The result was 16
(5x - 12)/3 = 16
Let's solve
Multiply both sides by 3
(5x - 12) = 48
Open brackets
5x - 12 = 48
Add 12 to both sides
5x = 60
Divide by 5 on both sides to isolate x
x = 12
Cindy is 12 years old.