The decimal from is 6 1/4 - follow me on Instagram @web.bie
W+D=659
W=D-91
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(D-91)+D=659
D-91+D=659
2D=750
D=750/2=375
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W+375=659
W=284
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So the dryer had cost $375 and the washer had cost $284.
Suppose you add x liters of pure water to the 10 L of 25% acid solution. The new solution's volume is x + 10 L. Each L of pure water contributes no acid, while the starting solution contains 2.5 L of acid. So in the new solution, you end up with a concentration of (2.5 L)/(x + 10 L), and you want this concentration to be 10%. So we have

and so you would need to add 15 L of pure water to get the desired concentration of acid.
It is 9. You have to add 33y, then divide by 11 and you get x = 3y + 9
1. -3
2. 28
3. 88
4. -5
5. -28