Answer:
The answer to your question is $ 23
Step-by-step explanation:
Data
Initial cost = $20
tip = 15 %
Total payment
Process
1.- Calculate the 15% of $20, considering that $20 is 100%.
$20 ---------------- 100 %
x ---------------- 15%
x = (15% x $20) / 100%
x = $300 / 100
x = $3
2.- Total payment
P = $20 + $3
P = $23
3.- Conclusion
Theresa payed $23 for the manicure