A restaurant customer left $2.60 as a tip. The tax was 5% and the tip was 20% of the after tax cost. Which information is not needed to compute the bill after tax and tip? What was the total bill?

The tax rate is not needed

Total bill cost = $13

Step-by-step explanation:

Given that :

Tip left = 2.60

Tax = 5%

Tip left = 20% of after tax cost

To calculate the total bill amount, we do not need information about the tax rate.

Since the total amount paid = after tax amount

Tip left = 2.60 is equal to 20% the after tax cost

Let after tax amount = t

Then,

20% of t = 2.60

(20/100) * t = 2.60

0.2t = 2.60

t = 2.60/0.2

t = 13

Hence, total bill is $13

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.