Question 457451
If 7 more than 3 x a number is added to a difference of 5 x a number and 10 the result is 3o.  Find the number. 
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Equation:
3x + 7 + 5x + 10 = 30
8x + 17 = 30
8x = 13
x = 13/8
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#2 how much of a 50% acid Solution should be combined with 10% acid solution to make 200 ounces of a 40% solution. 
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Equation:
acid + acid = acid
0.50x + 0.10(200-x) = 0.40*200
Multiply thru by 100 to get:
50x + 10*200-10x = 40*200
4ox = 30*200
x = 30*5
x = 150 ounces (amt. of 50% solution needed)
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200-x = 50 ounces (amt of 10% solution needed
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#3 twice the difference of a number and eight is equal to three times the sum of the number and 3. Find the number. 
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2(x-8) = 3(x+3)
2x-16 = 3x+9
x = -25
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Cheers,
Stan H.
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If you can show the work so I will be able to learn as well as show my child.