Answer:
price before tip (b) = $26
Step-by-step explanation:
29.90 is INCLUDING tip, so the real bill, b, would be less.
Now, since 29.90 is including 15% tip, and we let the original bill be "b", we can say:
b INCREASED by 15% gives us 29.90
We need to come up with an equation and solve for b.
15% means 15/100 = 0.15
Now, we can write:
b + 15% of b = 29.90
or
b + 0.15b = 29.90
then
1.15b = 29.90
b = 29.90/1.15
b = 26
So, price before tip (b) = $26
