Answer:
24 g butter 
12 g sugar 
36 g flour
Explanation:
The recipe makes 30 shortbread fingers.
She wants to make 6 fingers.
6/30 = 1/5
She wants to make 1/5 of the recipe, so she needs 1/5 of each ingredient's amount.
Divide each amount by 5.
Recipe: 
Makes 30 30/5 = 6 Makes 6 
120 g butter 120/5 = 24 24 g butter 
60 g sugar 60/5 = 12 12 g sugar 
180 g flour 180/5 = 36 36 g flour