## Thursday, November 29, 2012

### Speed

You are in your car going 5 miles in 4 minutes. What is your speed in miles per hour?

## Friday, November 16, 2012

### Scones

A recipe for scones calls for 3 cups of flour and 10 tablespoons of butter and makes 12 scones. You only have 2 cups of flour, but you can still make 8 scones. How much butter should you use?

*(Hint: 1 tablespoon = 3 teaspoons.)*## Thursday, November 15, 2012

## Wednesday, November 14, 2012

### Coin Stacks II

It is possible to mix coins in a stack to get a stack a whole number of millimeters high. For example, a stack of 2 nickels and 2 pennies has a height of exactly 2 × 1.95 + 2 × 1.55 = 7 mm. Can you find a stack of coins with a whole number of millimeters less than 7?

### Coin Stacks

US coins have different thicknesses as specified below:

Two stacks of coins may have the same height but a different number of coins. For example, a stack of 39 pennies has a height of 39 × 1.55 = 60.45 mm, and a stack of 31 nickels also has a height of 31 × 1.95 = 60.45 mm. Find the smallest number of dimes and quarters that can likewise be made into two stacks the same height.

Penny | 1.55 mm |

Nickel | 1.95 mm |

Dime | 1.35 mm |

Quarter | 1.75 mm |

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