Posted by Christina on Tuesday, January 12, 2010 at 9:26pm.
Sally's collection of quarters and dimes contains $32.85. There are 171 coins in all. How many quarters and dimes are in Sally's collection?
Can you show me the two equations you got and explain
Thanks

Algebra  drwls, Wednesday, January 13, 2010 at 12:02am
25 Q + 10 D = 3285 (the total number of cents)
Q + D = 171 (the total number of coins)
To solve, multiply the second equation by 10.
10 Q + 10D = 1710
Now subtract one equation from the other.
15 Q = 1575
Q = 105
D = 171  105 = 66