Thread: solving basic equations

The cost of a meal, including a 20% tip, is $21.60. How much was the meal without the tip?
The tip is 20% of x or 0.2x
Together, x + 0.2x =$21.60
1.2x =21.6
x = 18
what does x = in 0.2x and how would you find it

Originally Posted by Leona_Marie

The cost of a meal, including a 20% tip, is $21.60. How much was the meal without the tip?
The tip is 20% of x or 0.2x
Together, x + 0.2x =$21.60
1.2x =21.6
x = 18
what does x = in 0.2x and how would you find it

0.2 x is the percentage (20%) as a decimal

Originally Posted by Leona_Marie
The cost of a meal, including a 20% tip, is $21.60. How much was the meal without the tip?
The tip is 20% of x or 0.2x
Together, x + 0.2x =$21.60
1.2x =21.6
x = 18
what does x = in 0.2x and how would you find it


When you want to find out what the percentage of something is, you multiply it by that percentage. If you have 20% of $1 you have 20 cents.

Think about it this way: If you have $1.00, you have 100% of it. If you give me 20 cents you will have $0.80 cents left over. Look at what 80 cents look like --> 0.80 which is the same as 80%
So you gave me 20% of your dollar and you have 80% left.

x is your unknown value. What is the unknown value that the question asks for or what are you trying to find by solving this equation? The original cost of the meal, right? So that is what x would be!
x + .2x = 21.6 --> x = original cost of meal, .2x = cost of meal x 20% of that cost

Originally Posted by mollymcf2009

Originally Posted by Leona_Marie
The cost of a meal, including a 20% tip, is $21.60. How much was the meal without the tip?
The tip is 20% of x or 0.2x
Together, x + 0.2x =$21.60
1.2x =21.6
x = 18
what does x = in 0.2x and how would you find it


When you want to find out what the percentage of something is, you multiply it by that percentage. If you have 20% of $1 you have 20 cents.

Think about it this way: If you have $1.00, you have 100% of it. If you give me 20 cents you will have $0.80 cents left over. Look at what 80 cents look like --> 0.80 which is the same as 80%
So you gave me 20% of your dollar and you have 80% left.

x is your unknown value. What is the unknown value that the question asks for or what are you trying to find by solving this equation? The original cost of the meal, right? So that is what x would be!
x + .2x = 21.6 --> x = original cost of meal, .2x = cost of meal x 20% of that cost

molly, thank you that was the answer I was looking for