This question is best done with a table.
You'll need something like this:
New Used TOTAL
R
G
Fill out what we know:
New Used TOTAL
R 5
G 12
------------------
5 20
This is filled out with the information that 1/4 (five of them) are new, 1/4 (5 of them) are red, and exactly 12 are used and green.
Now we can take this information and fill out what else it implies (I've starred these):
New Used TOTAL
R 2* 3* 5
G 3* 12 15*
------------------
5 15* 20
We're asked how many are new and green, which is this one:
New Used TOTAL
R 2* 3* 5
G
3* 12 15*
------------------
5 15* 20
The answer is B.
_________________
GRE / GMAT Tutor London and Online since 2005. Writer, editor, contributor for test-prep materials.
Struggling with Permutations and Combinations (Combinatorics?). I've put loads of free resources here:
https://privategmattutor.london/gmat-combinatorics-ultimate-guide-to-gmat-permutations-and-combinations/As ever, feel free to get in touch for impartial GRE / GMAT advice or to enquire about lessons at:
https://privategmattutor.london