word problem

Question

I started working at 15. I spent 1/4 of my working life in a factory. I spent 1/5 of my working life in an office, and I spent 1/3 of my working life as a school caretaker. For the last 13 years of my working life I've been Santa Claus. How old am I

 

 

let x for his age

x-15 for working life

so

x=(x-15)1/4+(x-15)1/5+(x-15)1/3+13

x=5

i know his age and working life is not equal but how i form equation to find out his age

is this non equation type problem. Then how to find out equation problems and non equation type problems

 

 

Answer 1

Let x = the man's working life (not his age).

 

(1/4)x + (1/5)x + (1/3)x + 13 = x

 

(47/60)x + 13 = x

 

13 = x - (47/60)x

 

13 = (13/60)x

 

60 = x

 

The man has been working for 60 years.  Since he started working when he was 15, he is 15 + 60 = 75 years old.