# Really hard math algebra question?

To answer this question you MUST create an algebraic formula that includes all the information given. I will not get marks if I did trial and error.

There’s a box with 30 coins in it. The total value of all the coins combined is .75. There are also only quarters and loonies ( dollar bills if your not Canadian) inside the box.

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(Solving in cents)

Number of quarters = x

Number of loonies = y

25x + 100y = 1275…eqn 1

x + y = 30 (total of 30 coins)

x = 30-y…eqn 2

Plug in the value of x from eqn 1 into eqn 2:

25(30-y) + 100y = 1275

750-25y+100y = 1275

75y = 525

y = 7

Therefore:

# of quarters (30-y) = 30-7 = 23

# of loonies (y) = 7

Check:

7 loonies = $7

23 quarters = 23*0.25 = $5.75

Total = $12.75…which checks out with the question.

Q = number of quarters

D = number of dollars

Q + D = 30

Q = 30 − D … equation 1

(0.25)Q + (1)D = 12.75 … equation 2

Substitute equation 1 into equation 2:

(0.25)(30 − D) + (1)D = 12.75

7.5 − (0.25)D + D = 12.75

(0.75)D = 5.25

D = 7 … dollars or loonies

Q = 30 − D … equation 1

Q = 30 − 7

Q = 23 … quarters