Writing Systems
Systems with Coins
100
A student bought 3 boxes of pencils and 2 boxes of pens for $6. He then bought 2 boxes of pencils and 4 boxes of pens for $8.
3x + 2y = 6
2x + 4y = 8
100
Penny: $0.01
Nickel: $0.05
Dime: $0.10
Quarter: $0.25
200
Tina bought 6 packages of doughnuts and 4 packages of cookies for $38. Jovani bought 4 packages of doughnuts and 8 packages of cookies for $48.
6x + 4y = 38
4x + 8y = 48
200
Dennis mowed his next door neighbor’s lawn for a handful of dimes and nickels, 80 coins in all. Upon completing the job he counted out the coins and it came to $6.60.
d + n = 80
0.10d + 0.05n = 6.60
300
For a class picnic, one teacher purchased 18 juice boxes and 32 bottles of water, and spent $19.92. The other teacher purchased 14 juice boxes and 26 bottles of water, and spent $15.76.
juice box = j
bottle of water = w
18j + 32w = 19.92
14j + 26w = 15.76
300
Linda has 36 coins totaling $3.00, and the coins are all nickels, and quarters.
n + q = 36
0.05n + 0.25q = 3.00
400
To watch a varsity basketball game, spectators must buy a ticket at the door. The cost of an adult ticket is $3.00 and the cost of a student ticket is $1.50. If the school earned $352.50 selling tickets, and 180 people attended the basketball game.
a = adult tickets
s = student tickets
a + s = 180
3a + 1.50s = 352.50
400
In Sam’s piggy bank there are 11 coins that have a value of $1.85. The coins are either quarters or dimes.
q + d = 11
0.25q + 0.10d = 1.85