Answer :
hello!
What is [tex]\sf{\displaystyle\frac{1}{4}}[/tex] of 12?
In order to find it, we should divide 12 by 4:-
3
Now, solve our word problem:-
Matthew bought 12 roses. [tex]\sf{\displaystyle\frac{1}{4} }[/tex] of these roses were white.
And we already know how to solve this problem :)
Hence,
[tex]\bigstar{\boxed{\pmb{3~of~the~roses~were~white}}}[/tex]
note:-
Hope everything is clear; if you need any clarification/explanation, kindly let me know, and I will comment and/or edit my answer :)