Solution:
As per the problem we have 
Jason baked 7 pans of brownies he gave 1/4 of the brownies to his two sisters.
we have been asked to find 
How many pans of brownies did he give to his sisters.
we can find this by dividing the 7 by 1/4, because this is the exact portion that Jason gave to his sister.
Jason gave 
 pans of brownies to his sister.
 pans of brownies to his sister.
or 
Jason gave 
 pans of brownies to his sister.
 pans of brownies to his sister.