Posted by Libuse on .
A collection of nickels, dimes, and quarters amounts to $9.50. If there are 130 coins in all and there are twice as many dimes as there are quarters, find the number of nickels.

algebra 
Reiny,
number of quarters  x
number of dimes  2x
number of nickels  130  x  2x = 1303x
5(1303x) + 10(2x) + 25x = 950
650  15x + 20x + 25x = 950
30x = 300
x = 10
So there were 100 nickels
Check:
so 10 quarters > $2.50
20 dimes and > $2.00
100 nickels > $5.00 >total = $9.50 
algebra 
Libuse,
:)