SOLUTION: A student had 100 coins totalling $7.00. He had no nickels. What coins did he have if 60% of the coins were of one kind?

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Question 426689: A student had 100 coins totalling $7.00.
He had no nickels.
What coins did he have if 60% of the coins were of one kind?
Answer by jorel1380(3719) About Me  (Show Source):
You can put this solution on YOUR website!
Assuming no half-dollars as well as no nickels, all the student has are pennies, dimes, and quarters. He can't have 60 quarters, because that's too much. Similarly, dimes won't work out. He must therefore have 60 pennies.
$7.00-$.60=6.40
x+y=40
10x+25y=640
10x+10y=400
15y=240
y=16
x=24
Thus, our student has 60 pennies, 24 dimes, and 16 quarters..