Answer:
is the answer.
Step-by-step explanation:
The question has some typo errors.
Rashid and Mikhail submitted a total of x pastries to a baking competition.
Suppose say :
Mikhail made x pastries .
Hence Rashid made
pastries.
And in total they made
pastries.
Now we have that out of x,
of x were brushed with olive oil.
So,
of x that is
are brushed by butter.
So, it becomes 
=
= 
Hence, answer is option B.