Answer: On October 21, 1982, the Bureau of the Mint
Chapter 1, Problem 1.140(choose chapter or problem)
On October 21, 1982, the Bureau of the Mint changed the composition of pennies (see Exercise 112). Instead of an alloy of 95% Cu and 5% Zn by mass, a core of 99.2% Zn and 0.8% Cu with a thin shell of copper was adopted. The overall composition of the new penny was 97.6% Zn and 2.4% Cu by mass. Does this account for the difference in mass among the pennies in Exercise 112? Assume the volume of the individual metals that make up each penny can be added together to give the overall volume of the penny, and assume each penny is the same size. (Density of Cu 5 8.96 g/cm3 ; density of Zn 5 7.14 g/cm3 .)
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