Well, we to count the ratio of pizza place per person first
total people in north = 15 x 221 = 3315
Total people in south = 22 x 150 = 3300
Ratio in north = 32/3315 = 0.00965
Ration in south = 28/3300 = 0.00848
They said they want to open if the ratio is less than 0.01 , So i think both south and north are viable options
hope this helps