Question

There are 31 coins of dimes and quarters. If the number of dimes is 5 more than the number of quarters, how many quarters are there? How many are dimes? Hint: let x=dimes and y=quarters. Write your answer in an ordered pair ( , ).

Answer 1

13 Quarters

Explanation:

Let D and Q stand for the numbers of Dimes and Quarters.

We are told that:

D + Q = 31

We also find that:

D = Q + 5

Use the second expression (for D) in place of D in the first equation:

D + Q = 31

(Q+5) + Q = 31

2Q = 26

Q = 13

This means there are:

D = 13 + 5 or 18 Dimes

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Check

D + Q = 31 ?

18 + 13 = 31 YES

D = Q + 5 ?

18 = 13 + 5 YES