Phoebe is having 20 guests and Monica charges $25.00 per person so that’s 20*25 = $<<20*25=500.00>>500.00
Phoebe is a repeat customer so she gets 10% off of $500.00 so that’s .10*500 = $<<10*.01*500=50.00>>50.00 discount
Monica is charging $500.00 minus the repeat customer discount of $50.00 so she will make 500-50 = $<<500-50=450.00>>450.00
#### 450