Buster is three years younger than his sister Lupita. If the sum of their ages is 37, how old are they?

Question

I'm having problems with this problem

Answer 1

to answer this lets first setup some expressions that model this problem. First lets establish that Y = Lupita's age X = Buster's age and therefore we can say:

 

Y = X + 3

 

X + Y = 37

 

Now we have a system of equations we can solve by substitution. If we sub in the Y value from equation 1 into equation 2 we get

 

X + (X + 3) = 37 --> 2X + 3 = 37 --> X = 17

 

All that is left at this point is to find Y. From equation 1 we know that Y = X + 3 therefore Y = 20.

 

Answer 2

Buster + 3 = Lupita

 

Buster + Lupita = 37

 

 

Buster + ( Buster + 3 ) = 37 ;   2 Buster = 37 - 3 ;   2 Buster = 34 

 

Buster is 17 years old and Lupita is 20 years old.