A change machine changes dollar bills into quarters and nickels. lf you receive 12 coins after inserting a dollar bill, how many nickels did you receive?

Answer 1

#10#

If we write #n# for the number of nickels (5c) and #q# for the number of quarters (25c), then we have two simultaneous equations:

#100 = 25q+5n#

#12 = q+n#

Dividing both sides of the first equation by #5# we get:

#20 = 5q+n#

Multiplying both sides of the second equation by #5# we get:

#60 = 5q+5n#

After deducting the preceding equation, we arrive at:

#40 = 4n#

Dividing both sides by #4# and transposing, we find:

#n = 10#

So there were #10# nickels, making #50#c and #2# quarters, making the other #50#c.

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Answer 2

Eva Abramson

You received 8 nickels.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.