Question

Solve using graphing substitution or elimination in the picture

Answer 1

• 1) 18 quarters and 30 nickels
• 2) 8 quarters and 12 nickels

Explanation:

1) Let quarters be x and nickels be y.

Equations based on given, 48 coins, total of $6 = 600c:

• x + y = 48
• 25x + 5y = 600

Substitute y in the second equation, y = 48 - x

• 25x + 5(48 - x) = 600
• 25x + 240 - 5x = 600
• 20x = 360
• x = 18

Then value of y is:

• y = 48 - 18 = 30

2) Similarly to problem 1.

• x + y = 20
• 25x + 5y = 260

Substitution: y= 20 - x

• 25x + 5(20 - x) = 260
• 25x + 100 - 5x = 260
• 20x = 160
• x = 8

Then finding y:

• y = 20 - 8 = 12