3x-4 is the answer, you have to see that if its 3 times her nieces age it would be 3x and if its four less than that it is 3x-4
The formula for the volume of a sphere is V = (4/3) * π * r³. Knowing this, we can plug in the radius:

The sphere's volume is approximately 2144.66 mm^3.
The lowest common multiple is 216 (D)
I think the answer is c -6.5<6.55