Question 910137: 3. Ted has $6.80 in quarters and dimes. The number of dimes is 3 times the number of quarters. Which system of equations can be used to find q, the number of quarters, and d, the number of dimes, that Ted has?
Answer by Edwin McCravy(20081)   (Show Source):
You can put this solution on YOUR website!
Avoid decimals by thinking only in cents (pennies)
3. Ted has $6.80 in quarters and dimes.
That's 680 pennies!
25q + 10d = 680
The number of dimes is 3 times the number of quarters.
d = 3q
Which system of equations can be used to find q, the number of quarters,
and d, the number of dimes, that Ted has?
This system:
Trouble is, there is no way there could be any solution.
12 quarters and 3 times as many dimes, which is 36 dimes, comes
to only 660 ($6.60) <-- we're 20 cents short!
And then 13 quarters and 3 times as many dimes or 39 dimes comes
to 715 ($7.15)
That's way over $6.80. So we can't have 3 times as many dimes as
quarters and have $6.80.
The closest you could come is 12 quarters and 38 dimes
[ 12*25 + 38*10 = 300 + 380 = 680 ($6.80)
Your problem is botched.
Maybe it was supposed to be:
The number of quarters is 3 times the number of dimes.
Then you could have 24 quarters and 8 dimes because
8*3=24 and 24*25+8*10 = 600+80 = 680 ($6.80)
Edwin
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