Question 996114: A money box contains only 10-cent
and 20-cent coins. There are 34
coins with a total value of $5.40.
How many coins of each?
Answer by ikleyn(52900)   (Show Source):
You can put this solution on YOUR website! .
A money box contains only 10-cent and 20-cent coins. There are 34 coins with a total value of $5.40. How many coins of each?
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Let me solve it by an unusual way.
Let us suppose for a moment that all 34 coins are 10-cent.
Then their value is $3.40. It is less than $5.40 exactly in $2 = 200 cents.
It is clear that the difference is due to presence of 20-cent coins,
and it is also clear that the number of these 20-cent coins is 20 to cover the difference.
So, the answer is: 20 of 20-cent coins and 34-20 = 14 of 10-cent coins.
Notice. According to this article of Wikipedia, "The American twenty-cent piece is a coin struck
from 1875 to 1878, but only for collectors in the final two years."
20-cent coins are currently in use in Australia (see here).
If you want to see more problems solved in this way, look into these lessons
- Problem on two-wheel and three-wheel bicycles,
- Problem on animals at a farm and
- Problem on pills in containers
in this site.
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