Pre-Algebra help! 3 replies

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I didn't make it!

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#1 12 years ago

I am 14 and I'm kinda behind in math. I can do it OK, but the word problems just fuck everything up with me. Can somebody please explain how to write an equation out of these? You don't have to solve them. I can do that easy. But I just can't figure it out!!!!!! My dad can't even figure it out. He has forgotten a lot sense he hasn't been in school for 30 years now. I think they should be pretty easy to some of you.

1. The cost of a medium pizza is %80 of the cost of a large pizza. If the total cost for 1 medium pizza and 1 large pizza is $24.30, what is the cost of each size pizza?

2. On his evening route, a newspaper carrier has 8 more than 3 times the number of his morning customers. If he has 98 customers on his evening route, how many customers does he have on his morning route?

3.Richard works part-time as a waiter. One week he worked 15 hours and received $67.50 in tips. His wages and tips totalled $128.25. What was his hourly wage?

It's not that I need the answers. I just need to get an idea of what goes where and how to do it. So don't accuse me or flame me saying that I am a cheater please.




DarthParrot

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#2 12 years ago

1: So, we know that we have two pizzas, the only real difference is that one costs 80% other the other. We also know that both of them added together equals $24.30.

Therefore the equation In layman's terms looks like: 80% pizza cost + pizza cost = $24.30

We don't know what the cost of the pizza is, so lets make this equation a little more simple and just replace pizza cost with a variable, say X.

We should get: 0.8X + X = 24.30 (0.8 multiplied by any number will get you 80% of that number)

From here, we combine like terms to get: 1.8X = 24.30, then we just divide both sides by 1.8 to get X = $13.50 2: For number two, the equation in layman's terms should look like: 98 evening customers = 3(the number of morning customers) + 8.

We don't know how many morning customers there are, so we replace that with a variable an are given the traditional equation: 98 = 3X + 8. From here you just subtract 8 from 98 and divide it by 3 to get X = 30.

3: Ok, so here we know that the total value is $128.25, so in the equation we'd set this to equal everything else combined since it's the total value. We also know that he received $67.50, that will serve as our constant since it's a solid number that doesn't change. Finally we know that he works fifteen hours, what we don't know is how much he makes per hour, so we'd set this up as: 15 times (the amount he makes per hour) or 15X.

Overall, the equation should look like this: 128.25 = 15X + 67.50.

From here, you just subtract 67.50 from 128.25 to get 60.75, then divide it by 15 to get the amount he makes per hour or $4.05.

(Random thought: jeeze that's under minimum wage...)

In the future when reading word problems, be on the lookout for key words such as "more than, less than, so many times a number." clues such as those give you hints as to what's being added or subtracted from what and where the variable goes. Just remember, ignore the fluff and focus on the numbers given and whether to add, subtract, etc.

Also, one other thing, when you can't figure out how to solve a problem. Trying finding the answer you should be getting in the back of the book and work backwards from there to try and figure how you would go about solveing that problem. It's not cheating, it's learning; once you figure it out from reverse engineering you'll know how to do it perfectly in the future and won't need to use the back of the book and those types of problems in the future. ;)

I hope this helps, if you have any more questions feel free to ask. :)




Speer

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#3 12 years ago

I remember doing this stuff, though once you get it down it becomes quite easy.

It seems that Darth Parrot knows what he is doing, so I won't interfere.




Kilobyte

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#4 12 years ago

Darth Parrot did it well, so I will keep mine simple. However, I have virtually Highlighted, and added some notes to try to help. ( = '?') It to tell you what the previous key word means, and the context to follow, is how it is supposed to be interpreted.

I underlined the part that mentions the goal. Also, I dropped some of the information in the notes below the quotes, to show you how to seperate the information.

The bold tells you what you need to pay attention to. You need to look for hints in the keywords, And, Less Than, More than, of, is, totalled, Difference of, Difference between, or, etc...

Cock'n'Balls;4410336 1. The cost of a medium pizza is %80 of (= '*') the cost of a large pizza. If the total cost for 1 medium pizza and(= '+') 1 large pizza is(= '=') $24.30, what is the cost of each size pizza?[/quote]

Medium = 80% or 0.8 * Large Large = ?

M + L = $24.30

What is the cost of each pizza? Solve for "M", and Solve for "L".

Substitute "L" for "M" (0.8L) + L = $24.30

Cock'n'Balls;44103362. On his evening route, a newspaper carrier has 8 more than(8+) 3 times{ 8 + (3 * ?) } the number of his morning customers (=?).

If he has 98 customers { 98 = 8 + (3 * ?) } on his evening route, how many customers does he have on his morning route?

Morning Customers = ? Evening Customers = 98

Evening Customers = 8 More than 3 Times the Morning Customers Morning Customers = A third (1/3) of 8 less than the Evening Customers.

[QUOTE=Cock'n'Balls;4410336]3.Richard works part-time as a waiter (Ignore). One week he worked 15 hours (15 * h) and(= '+') received $67.50 in tips (15h + $67.50).

His wages and tips totalled $128.25 { (15h + $67.50) = $128.25 }.

What was his hourly wage? What does "h" equal? Where "h" is "Income Per Hour".

Worked 15 hours in a week Made $67.50 in tips. Earned $128.25 total.

Amount earned = 15 hours, plus $67.50 in tips. Solve for Hours (Dollars per hour),...

$128.25 = (15 hours) + $67.50 Convert "Hours" to a variable, and ignore the dollar signs for now.

128.25 = 15h + 67.50

Actually, that is good money over here, where minimum wage for waiters is $3.00. Hopefully this helped, and didn't confuse.