Answer: volume of prism A = 1080 cm^3
Step-by-step explanation:
From the diagram, 
length of prism A = 15
length of prism B = 5
Scale factor = 15/5 = 3
Since we want to calculate volume, 
scale factor of volume = 3^3 = 27
Thus, 
volume of prism A/Volume of prism B = 27
Given that Volume of prism B = 40, then
volume of prism A/40 = 27
volume of prism A = 27 x 40
volume of prism A = 1080 cm^3