Here's the question you clicked on:
Claire4christ
And i need help with these problem. An alloy of tin is 15% tin and weighs 20 pounds. A second alloy is 10% tin. How much (to the nearest tenth lb.) of the second alloy must be added to the first alloy to get a 12% mixture. ______ pounds
Problem 1: A jeweler is using an alloy, a mixture of metals. He has 10 pounds of the alloy. 2% is the rare metal robium. He has another source which is 5% robium. He wishes to combine these mixtures to form a mixture that is 3% robium. Solution: 1. Identify the variables. (0.02)(10) The quantity of robium in material 1 (5%)(x) The quantity of robium in material 2 (0.03)(x+10) The quantity of the desired mixture 2. Write an equation. 5% x + (0.02)(10) = (0.03)(x+10) The equation required. 3. Perform the Solution. 0.05x + 0.2 = .03x + 0.3 = 0.02x = 0.1 4. Write the answer. x = 5 The desired amount.
just do what i did. use the percent bar, then the butterfly method. want me to start for you? here: |dw:1349374188909:dw|
sorry its not clear to me i can't see the top number
at the very top, it isn't a number, its the % symbol. all you do is fill it in, the top number, is the number your trying to find, x, the bottom number, not the 100, is the total, then you put what percent you are trying to find below the percent sign and above the 100.
so its (0.15)(20) (10%)(x) (0.12)(x+10)
15 * 20 + 10x = 12 ( 20 + x) @Claire4christ Can you continue?
did you see example above???
If you are talking about your post, then it's WRONG!
that's one of the examples
do you see where it says problem 1 that;s the example
can u explain me than plz
I just show you the result equation, then you solve it yourself!
Multiply the percentage with its mass :)
Is it clear to you now?
15 * 20 + 10x = 12 ( 20 + x) 300 + 10x = 240 + 12x
Do you understand my calculation above?
Where do you get 60+10x=2x?
15 * 20 + 10x = 12 ( 20 + x) 300 + 10x = 240 + 12x -> 2x = 60 You should make each line worth your while, instead of jumping all over !!!
Now I hope you're fine with x = ...?
how did you get 15
I just make your life easier by multiplying all with 100 :)