Complete question :
A restaurant customer left $0.90 as a tip. The tax was 8% and the tip was 10% of the after tax cost. Which information is not needed to compute the bill after tax and tip? What was the total bill?
Answer:
The tax percentage
9.9
Step-by-step explanation:
Guven that :
Amount of tip left = 0.90
Tip left = 10% of after tax cost
Tax % = 8%
If tip left = 10% of after tax cost; then ;
If after tax cost = x
10% of x = 0.90
0.1x = 0.9
Hence the percentage tax isn't needed :
To obtain the total bill:
Let total bill = y
y = after tax cost and tip
Hence,
y = x + tip
y = x + 0.9
From : 0.1x = 0.9 ; x = 0.9/0.1 = 9
Hence,
Total bill:
y = 9 + 0.9
y = 9.9
