Answer:
60 nickels
Step-by-step explanation:
When a ratio between coins is given, I like to consider the problem in terms of groups of coins. Here, each group would consist of 1 nickel and 0.20 quarters. The value of that group is
5¢ +0.20×25¢ = 10¢
Then the number of groups is ...
(total value)/(value of 1 group) = number of groups
600¢/10¢ = 60
Since each group has 1 nickel, there are 60 nickels.
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Check
60 nickels + 12 quarters = $3.00 +3.00 = $6.00
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Additional comment
If you want to see this with equations and variables, you can do this.
Let n and q represent the numbers of nickels and quarters, respectively. The given relations are ...
0.05n +0.25q = 6.00
q = 0.20n
Substituting for q in the first equation gives ...
0.05n +(0.25)(0.20n) = 6.00
Simplifying gives ...
0.10n = 6.00
n = 6.00/0.10 = 60
