The Smith Family went out for dinner.

The price of the meal was $29.85.
The sales tax was 6% of the price of the meal.
The tip was 15% of the meal and the sales tax.

How much money did the smith family pay for the meal, including tax and tip?

The Smith family price for the meal is  $36.39

Step-by-step explanation:

The Smith family went out to dinner. • The price of the meal was $29.85.

The sales tax was 6% of the price of the meal.

LEts find sales tax amount

sales tax amount = price of meal * sales tax 6%(0.06)

= 29.85 * 0.06 = 1.791

sales tax amount = 1.791

Price of the mean with sales tax = 29.85 + 1.791= 31.641

The tip was 15% of the meal and the sales tax

now we find out tip amount for 31.641

15 % is 15/ 100 = 0.15

Tip amount = 31.641 * 0.15 = 4.74615

Now we add the top amount with 31.641

31.641+ 4.74615=36.38715

the Smith family price for the meal = $36.39

step-by-step explanation:

30% of $420 is 0.30($420) = $126 and $420 + $126 = $546.

or, 130% of $420 is 1.3($420) = $546.

notice that this is not the $600 original list price with which we started.

why doesn't this work?

the method does not work because 30% of $420 is not the same amount as the 30% of $600. it may seem obvious when stated this way, but it is a very common error made on problems of this type. we cannot just use the same percent and get back to the original amount because we are taking that percent of a different value.

to work problems of this type correctly, it is generally best to write an equation for the situation and then solve.

example: since (100% – 30%)(original price) = (sale price)

70% of the   (original price) is $420.

0.7x   = 420

equation image indicator

x = 600

the original cost was $600.

we may also solve this problem using the two-step method. working the problem in two steps requires us to use more algebra skills. we have to know that x = 1x (identity property of multiplicationtext annotation indicator) and that 1x – 0.3x = 0.7x (subtracting like terms). then we solve the problem as follows:

(original price) – 30%(original price) = sale price

x – 0.3x = 420

0.7x = $420

equation image indicator

x = 600

the original cost was $600.  

note that with both of the above methods we do obtain the correct original amount.

example: after a 5% pay raise, hermione is earning $22,680 per year. what was she earning before the pay raise?

105% of (original salary) = current salary

1.05x = 22,680

equation image indicator

x = 21,600

hermione earned $21,600 per year before the pay raise.

this is an example so maybe you will get how to at least do it!