Problems of the Month--October

Back Home At Last!

Loggerhead Sea Turtle General info:
Size: Typically 2.5 to 3.5 feet in carapace length (73-107 cm).

Weight: Adult weigh up to 350 pounds (159 kg).

Diet: Primarily carnivorous and feed mostly on shellfish that live on the bottom of the ocean. They eat horseshoe crabs, clams, mussels, and other invertebrates. Their powerful jaw muscles help them to easily crush the shellfish.

Habitat: Prefer to feed in coastal bays and estuaries, as well as in the shallow water along the continental shelves of the Atlantic, Pacific and Indian Oceans.

Nesting: Nest at intervals of 2, 3, or more years. They lay 4 to 7 nests per season, approximately 12 to 14 days apart. Lays average of between 100 to 126 eggs in each nest. Eggs incubate for about 60 days.

Status:U.S. - Listed as Threatened (likely to become endangered, in danger of extinction, within the foreseeable future) under the U.S. Federal Endangered Species Act.International - Listed as Endangered (facing a very high risk of extinction in the wild in the near future) by the International Union for Conservation of Nature and Natural Resources.

Threats to Survival: The greatest threat is loss of nesting habitat due to coastal development, predation of nests, and human disturbances (such as coastal lighting and housing developments) that cause disorientations during the emergence of hatchlings. Other major threats include incidental capture in longline fishing, shrimp trawling and pollution. Incidental capture in fisheries is thought to have played a significant role in the recent population declines observed for the loggerhead.
Population Estimate: 44,560 nesting females.

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On September 19, the National Aquarium in Baltimore released a Loggerhead Sea Turtle that had been in their care for over a year. The turtle was back home at last!

1. When the turtle was rescued it couldn’t swim or dive properly (both skills are needed for catching food). Part of the reason for his impairment was the 10 pounds of hitchhiking barnacles, mollusks, and sea grass that had attached themselves to the turtles shell. Once the 10 pounds of “hitchhikers” were removed they found the turtle was severely underweight! Weighing only 64 pounds with a clean shell, what percent of his weight at capture was due to the “hitchhikers”? Express your answer to the nearest tenth.

2. Once the turtle’s shell was cleaned off he was able to swim and dive properly which allowed him to catch food and enabled him to reach a healthy weight. Upon release, the turtle weighed 90 pounds, which is an ideal weight for the turtle!! By what percent did the turtle’s weight (without the hitchhikers) increase while in rehabilitation? Express your answer to the nearest thousandth.

3. To track where the turtle goes and how he is doing after his release, researchers attached a tracking device to his shell that will naturally fall off after a while. From the morning of September 19, 2009 to the morning of September 24, 2009, the turtle had swum 76.4 miles. If the turtle slept 10 hours each day, what was his average swimming speed in miles per hour during the times in which he was awake? Express your answer as a decimal to the nearest hundredth.

5th Grade Orientation Week

The students have had a great first week of school. So far, we have completed problem solving activites, and reviewed whole number operations. This is Mrs. Lawrence's homeroom, who spent the week with Mrs. Liotta for math class.

Welcome Back!!!

It is great to be back at Calvert School for the 2009-2010 school year. The Math Blog is a great place to find links to your textbooks and workbooks. There will also be problems of the month posted. Not only are the challenge problems fun, they also give you a chance to win prizes. Last year, as fifth graders, Joe Sakai and Tommy Diehl won gift cards from Cold Stone. Who will be the top winners this school year?

Problems of the Month--September

Cash for Clunkers

1. On July 31, 2009 the US government decided to make an additional two billion dollars available to the “Cash for Clunkers” program that is aimed at jump-starting the car industry. The bill was passed with a yes-to-no vote count of 316-to-109. What percent of the votes supported passing the bill? Express your answer to the nearest hundredth.

2. Jillian decides to take advantage of this program and trades in her old car (which only got 15 miles per gallon of gasoline) for a new car that gets 32 miles per gallon of gasoline. Gas currently costs $2.52 per gallon in her town. If she drives an average of 1000 miles per month and gas continues to average $2.52 per gallon, how much money will Jillian save on gas in one year?

3. Franklin is also taking advantage of the Cash for Clunker program and is trading in his car that got 18 miles per gallon of gas (which is the highest gas mileage that a car can get and still qualify as a “clunker”). The original price of the car he plans to purchase is $15,095, but because the new car will improve Franklin’s gas mileage by over 10 miles per gallon, he will get $4500 off of the price of the new car. If Franklin has to pay a 6% sales tax on the discounted price of this car, how much will he end-up paying for the car and the sales tax combined?