Varsity Math 113

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With the holidays almost upon us, the coach has some shopping puzzles to share with the team.

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Gifts

Prime Presents 1

Two days ago, Rachel bought some gifts, and each cost a prime number of dollars. When she wrote down all the prices, each digit from 1 to 9 was represented exactly once. The total bill was the minimum possible for this situation.

What was the bill and how many gifts did she buy?

Prime Presents 2

Yesterday, Alex bought some gifts, and each cost a prime number of dollars. When he wrote down all the prices, each digit from 0 to 9 was represented exactly once. The total bill was the minimum possible for this situation.

What was the bill and how many gifts did he buy?

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Solutions to week 112

For Precise Prescription, transfer water until the 5-ounce vial contains 4 ounces of water. Dissolve the tablet in this water. Measure out and discard 3 ounces of the mixture. Add 4 ounces of water to fill the 5-ounce vial. Measure out and discard 3 ounces of the resulting mixture. The required dose remains in the 5-ounce vial. In Gift Dilemma, the DVD set costs $33.

Precise Prescription answer explained: Notation: (A, B, fA, fB) indicates A ounces and fA of a tablet in the 5-ounce vial and B ounces and fB of a tablet in the 3-ounce vial. The first step always begins by filling one or other vial and proceeds in sequence after each step. Putting in the tablet is counted as a step.

12 steps are needed. (5,0,0,0), (2,3,0,0), (2,0,0,0), (0,2,0,0), (5,2,0,0), (4,3,0,0), (4,0,0,0), (4,0,1,0), (1,3,.25,.75), (1,0,.25,0), (5,0,.25,0), (2,3,.1,.15). The dose is now in the 5-ounce vial.

Recent Weeks

Week 112: Precise Prescription & Gift Dilemma, solutions to Pumpkin Crop & The Halloween Goblin

Week 111: Pumpkin Crop & The Halloween Goblin, solutions to Making 25 & Two Ways to 32

Week 110: Making 25 & Two Ways to 32, solutions to Commuters’ Dilemma & Construction Conundrum

Week 109: Commuters’ Dilemma & Construction Conundrum, solutions to Nine Coins & Five Questionable Coins

Week 108: Nine Coins & Five Questionable Coins, solutions to Ten from Two & Triangular Boundary

Links to all of the puzzles and solutions are on the Complete Varsity Math page.

Come back next week for answers and more puzzles.