When looking at a DS question it is often best to identify the content area and work with the original statements before looking at the numbered statements. Here is says that 1/4 of a larger number is greater than 5 times a smaller number - this is all algebra so it would be a good idea to set up the equation:
1/4(L)>5S now you can manipulate that to get the S on one side so you get 1/20(L)>S. Then incorporate the question which is S<4? If S is less than 4 then L would be less than 80 so that is the real question being asked - is L less than 80?
Statement 1 says L is greater than 70 which includes both numbers less than and greater than 80. So it is insufficient.
Statemetn 2 says that L is less than 80 which is the exact information we are looking for - and the answer is B.
Becky
Master GMAT Instructor
The Princeton Review
Irvine, CA