Answer:
Month since April Number of Ants 
 0 10,000
 1 30,000
 2 90,000
 3 270,000
 4 810,000
Every month, the ant population triples so the multiply the previous population by 3 to find out the new population. 
0 months from April = 10,000 * 1 = 10,000 ants
1 month from April = 10,000 * 3 = 30,000 ants 
2 months from April = 30,000 * 3 = 90,000 ants
3 months from April = 90,000 * 3 = 270,000 ants 
4 months from April = 270,000 * 3 = 810,000