Luis is 5 times as old as Tiffany and is also 40 years older than Tiffany.

How old is Luis?

If we assume the age of Tiffany is: x

Then the age of Luis would be: 5x

but it also would be: x+40

So we have equation: 5x = x+40

-x - x

4x = 40

:4 : 4

x = 10

x + 40 = 10 + 40 = 50

Luis is 50 years old