Anonymous asked in Science & MathematicsMathematics · 9 years ago

Help on some math? (Pre-Algebra-Algebra I)?

I need help and nobody is around to help. I really only need the formula, you don't need to work out the problem. it's preferred that you include only one variable in each.

1)A product is on sale for 30% discount. Maria paid $15.12, including a 8% sales tax. Find the original price of the product.

2) A 15-gallon salt-water solution contains 20% pure salt. how much water should be added to produce the solution to 15% salt? Irrelevant side note: I think the physics is wrong on this one lol)

3) A 200-gram chlorine-water solution contains 40% chlorine. How much water should be added to make a new solution that is only 25% chlorine?

4) There are one-dollar bills and five dollar bills in the piggy bank. It has 54 bills with a total value of $174. How many ones and five are in the bank?

5) John gave three fifths of his money to Joe and gave 40 to to Janet. John had $8 left. How much money did John had to start with?

6) Tom ate one-third of the candies in a box. Roger ate 2/5 of the remaining candies. There were 18 candies left. How many candies were in the box to start with?

2 Answers

  • Favorite Answer

    1- let C be the cost of the merchandize

    they deduct the discount then calculate the tax

    15.12 = C-(C* discount rate) + [C-(C* discount rate) ]*[tax rate]

    plug in solve for C


    gal ...........% of salt.......... final solution % of salt

    15 gal ....... (0.20) ............. (15+x) (0.15)

    15(0.20) + x(1.0) = (15+x)( 0.15), solve for x

    3 is similar to 2

  • 9 years ago

    1.) 15.12= .3x+.08(15.12)



    4.)174=x+5y and 54=x+y

    5.) (3/5)x+40=8


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