Problema Solution
Sally is Bob’s younger sister, and she is 7 years younger than Bob. If you multiply Bob’s age by three and subtract Sally’s age, you get their mother’s age, which is 37 years. How old is Sally?
Answer provided by our tutors
let
s = the age of Sally
b = the age of Bob
Sally is 7 years younger than Bob
s = b - 7
multiply Bob’s age by three and subtract Sally’s age, you get their mother’s age, which is 37 years
3b - s = 37
by solving the system of equations
s = b - 7
3b - s = 37
we find
s = 8 years
click here to see the step by step solution of the system of equations
Sally is 8 years old.