Question 268814
Let the width be x.
Then the length is 3x, since it is 3 times longer.
The diference between the length and the width is 8. 
Then let 3x-x=8
2x=8
x=4
So the width is 4.
The length is 3 times longer, so 3*4=12.
That makes the length equal 12.
Good luck!!