Audrey has $21.40 in dimes and quarters for a total of 100 coins. How many of each coin does Audrey have

Question

a systems of equation question and you should solve using elimination

Answer 1

Let # of dimes = x

Let # of quarters = y

 

 

We set up our equations

 

x + y = 100                            eq1

0.10x + 0.25y = 21.40              eq2

 

 

Substitute eq1 into eq2.

 

0.10x + 0.25(100 - x) = 21.40

0.10x + 25 - 0.25x = 21.40

-0.15x + 25 = 21.40

-0.15x = -3.60

        x = 24

 

Substitute this value into eq1.

 

y = 100 - x

y = 100 - 24

y = 76

 

Audrey has 24 dimes and 76 quarters.