Answer:
<u>Solution for (a)</u>
Earlier Copper pennies are 22.
After 1983 pennies are 28.
Step-by-step explanation:
Pennies minted after 1983 weigh 2.50g
Earlier copper pennies weigh 3.11g
A roll of pennies contains 50 pennies.
A particular roll of pennies weighs 138.42g
Let the number of pennies minted after 1983 be x and;
Earlier copper pennies be 50 - x
2.50x + 3.11(50 - x) = 138.42
Opening the brackets gives;
2.5x + 155.5 - 3.11x = 138.42
Solving like terms together gives;
-0.61x = -17.08
Dividing through gives;
x = 28
So there are 28 after 1983 pennies and;
50 - 28 = 22 earlier pennies.
