Age problem

Daniel is 28 years younger than Kevin.  Kevin and Daniel first met 3 years ago.  Eight years ago, Kevin was 5 times as old as Daniel.  How old is Daniel now?

k = Kevin's age now
k - 28 = Daniel's age now 

The fact that they met 3 years ago means nothing. 

k - 8 = Kevin's age 8 years ago   {subtracted 8 from Kevin's age now}
k - 36 = Daniel's age 8 years ago   {subtracted 8 from Daniel's age now} 

k - 8 = 5(k - 36)   {8 years ago, Kevin was 5 times as old as Daniel}
k - 8 = 5k - 180   {used distributive property}
-8 = 4k - 180   {subtracted k from each side}
4k = 172   {added 180 to each side}
k = 43   {divided each side by 4}
k - 28 = 15   {substituted 43, in for k, into k - 28} 

Daniel is 15 now.


- Algebra House