Question

Example
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.

Answer 1

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

Answer 2

(0.15)(20)
(10%)(x)
(0.12)(x+20)

Answer 3

so far right???

Answer 4

yess :)

Answer 5

so next
10%x(0.15)(20)=(0.12)(x+20) right

Answer 6

yess. seems like you have it figured out.

Answer 7

im confuse on last part

Answer 8

What do you need now Claire?

Answer 9

perform the solution

Answer 10

hrmmm i got .7 ?

Answer 11

you mean solve the following:
\[.1x(.15)(.20)=(.12)(x+20)?\]

Answer 12

.10x+3=.12x+2.4=

Answer 13

.10=.1 its 10, you don't need the 0, but it could be easier. to solve.
\[.1x+3=.12x+2.4\]\[.1x+.6=.12x\]\[.6=.11x\]\[x=1.833\infty(3)\]

Answer 14

so how did you get .6

Answer 15

.06* my bad 1 sec. \[.1x+.06=.12x\][\.06=.11x\]\[1.833\infty(3)=x\] oddly,its the same answer.

Answer 16

1.8 pounds???

Answer 17

you could always use the percent bar method. that's easiest.

Answer 18

so im confused how many pounds.

Answer 19

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.