Coin Value Estimation DIRECTIONS 1. Do not modify shaded cells. These cells contain formulas or other fixed information. If you change one by accident, open the original document. 2. Think of this spreadsheet as a \"virtual coin jar.\" In each row, you can adjust the quantity of each type of coin in the jar. This will change the total value of that coin type, the total weight of that coin type, and its percent in the jar, shown in the shaded columns. It will also change the value and weight of the jar, shown in the last row. To see how it all works, try this practice exercise. a. Set the quantity of each type of coin equal to 0. b. Increase the quantity of pennies to 10. Notice how its total value and weight, and the total value and weight of the jar, update. Because there are only pennies in the jar now, the percent of pennies is 100%. c. Increase the quantity of nickels to 10. Notice how its total value and weight, and the total value and weight of the jar, update. Because the total quantity is now half pennies and half nickels, the percent of pennies and nickels is now 50 percent for each type of coin. d. Increase the quantity of dimes to 10. Notice how its total value and weight, and the total value and weight of the jar, update. Because there is an equal amount of each of the three coin types, the percents are about 33 precent for each type of coin. e. Increase the quantity of quarters to 10. Notice how its total value and weight, and the total value and weight of the jar, update. Because there is an equal amount of each type of coin in the jar, the percents are now 25 percent for each type of coin. f. Spend about a minute changing the quantities and watching how the values in the spreadsheet change. 3. Your goal is to estimate the total value of an actual coin jar. The coins were thoroughly mixed up and a handful was randomly selected. The sample contained 30 pennies, 3 nickels, 9 dimes, and 13 quarters. Because the sample was a random sample, the percent of each type of coin in the sample is close to the percent of each type of coin in the jar. 4. Next, the coins were weighed and the total weight was found to be 1642 grams. In the spreadsheet, modify the quantities of each type of coin so that the percents are approximately equal to the percents you found and the total weight is about 1642 grams. 5. Use the spreadsheet to estimate the percent of each type of coin in the jar. When you get as close as you can to matching the percents and weight, record the total value of the coins, which is the estimated value of the coins in the jar. CALCULATIONS Quantity, n Total Value t = (n)(v) 1.05 Coin Mass (in g), k 2.50 Total Mass (in g), m = nk 262.50 Percent 24.76% Pennies 105 Coin Value, v 0.01 Nickels 105 0.05 5.25 5.00 525.00 24.76% Dimes 105 0.10 10.50 2.27 238.14 24.76% Quarters 109 0.25 27.25 5.67 618.03 25.71% Total 424 44.05 1643.67