Question 563466
David is the age of 58 and Lisa is the age of 18. 
How long ago was David 5 times the age of Lisa.
:
let y = the no. years ago that D was 5 times L's age
:
58 - y = 5(18-y)
58 - y = 90 - 5y
-y + 5y = 90 - 58
4y = 32