19 & 23 usei o processo de multplicar os números por um
4/3 * pi * radius^3 is the formula for volume of a sphere.
First of all the repeated digits numbers are 66,77 and 99 Total 3
Numbers beginning with 6 Total 3 (63,67 and 69).
Numbers begin with 7 Total3
and begin with 9 Total 3.
answer is 12
