I need to increase my sales by 35% this month I’m currently at 45 sales how many sales do I need to meet my goal ?

Assume that 100% = 45 sales and 35% = X sales amount

You can create a ratio to help you solve for x

45 = 100%
x   =  35 %

Which is equal to this fraction:  (45/x) = (100/35)

Solving for X by cross multiplying and dividing by 100:
  [(45)(35)] / 100  =  X = 15.75 = 16 sales (rounded up)

You would need at least 16 sales to increase sales total by 35%