The volume of the smaller candle is 8.64π cubic inches.
How to find the volume
The volume of a cylinder is given by the formula
V = π r² h,
where
r is the radius and
h is the height.
The scale factor is given as 3:5, which means the ratio of the volumes is (3³ : 5³)
Using the ratio, let volume of the the smaller candle. be x
3³ : 5³
x : 40π
cross multiply
x = 40π * 3³ / 5³
x = 40π * 27 / 125
x = 8.64π cubic inches.