Question

Which system of equations could be used to determine how many of each coin you have

Answer 1

Answer: Choice A

0.10d + 0.05n = 2.25

d = 2n

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Explanation:

n = number of nickels

d = number of dimes

we have twice as many dimes as nickels, so we could have something like 18 dimes and 9 nickels. Algebraically we would write d = 18 and n = 9. The equation that fits this is d = 2n. The answer is between A and B at this point.

We rule out choice B since the 0.05d is incorrect. It should be 0.10d to represent the total value of all the dimes.

Choice A is correct

d = number of dimes

0.10d = value of all the dimes in dollars

n = number of nickels

0.05n = value of all the nickels in dollars

0.10d + 0.05n = total value from both coins combined

2.25 =  total value from both coins combined

0.10d + 0.05n = 2.25