1. In 1983 the composition of pennies in the United States was changed due, in part, to the rising cost of copper. Pennies minted after 1983 weigh 2.30 grams while the earlier copper pennies weigh 3.01 grams.

A roll of pennies contains 50 coins. If a particular roll of pennies weighs 133.46 grams, how many of the old heavier pennies and how many of the new lighter pennies does this roll contain? (LT#4.12)

x + y = 50

2.3x + 3.01y = 133.46

Suppose you weigh a roll of pennies on a scale which only reads the weight to the nearest gram. The scale says that the roll of pennies weighs 143.40 grams. What can you conclude about the pennies in this roll? (LT#4.12/4.14)

2. Using technology, construct a system of two linear equations where (-2,3) is a solution to the first equation but not to the second equation, and where (-2,7) is a solution to your second equation but not your first and they have no solutions in common. Write your system of equations and explain how your graph shows that your system satisfies the required conditions. (LT#4.15)

3. All the horses and cows in a pasture have a total of 50 heads and 200 legs.

The system of equations for this would be, when x = # of horses and y = # of cows

Find a solution to the system and write a sentence interpreting the solution? (LT#4.15)

x + y = 50

4x + 4y = 200

desmos can help