Respuesta :
Sorry I mis-read the question, your answer is 151; Here is how I solved it:
January: $16
Febuary: 16 + 15 =31
March :31+15=46
April : 46+15=61
May: 61+15=76
June: 76+15= 91
July: 91+15= 106
August: 106+15= 121
September: 121+15= 136
October:136+15= 151
January: $16
Febuary: 16 + 15 =31
March :31+15=46
April : 46+15=61
May: 61+15=76
June: 76+15= 91
July: 91+15= 106
August: 106+15= 121
September: 121+15= 136
October:136+15= 151