SOLUTION: x+y = 250 5x+10y = 21.25 Can you help me solve this equation. In my problem x= nickles and y=dimes, how many dimes and how many nickles do I have? Thanks for your help, cou

Algebra ->  Expressions-with-variables -> SOLUTION: x+y = 250 5x+10y = 21.25 Can you help me solve this equation. In my problem x= nickles and y=dimes, how many dimes and how many nickles do I have? Thanks for your help, cou      Log On


   

Question 71801: x+y = 250
5x+10y = 21.25
Can you help me solve this equation. In my problem x= nickles and y=dimes, how many dimes and how many nickles do I have?
Thanks for your help, could you please show me the work. I am trying to help my son, he is in 9th grade Algebra I. This question is not from his text book, just a handout from his teacher.
Nancy
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
x + y = 250
I think the $amt equation should be
.05x + .10y = 21.25
:
In my problem x= nickels and y=dimes, how many dimes and how many nickels do I have?
:
Take the the 1st equation (total number of coins):
x + y = 250
:
Subtract y from both sides:
x = (250 - y)
:
Substitute (250-y) for x in the 2nd equation ($$ amount)
.05x + .10y = 21.25
.05(250-y) + .10y = 21.25
:
Mult what is inside the brackets:
12.50 - .05y + .10y = 21.25
:
Subtract 12.50 from both sides:
-.05y + .10y = 21.25 - 12.50
+.05y = 8.75
:
Divide both sides by .05 and you have the value of y (dimes)
y = 8.75/.05
y = 175 dimes:
:
Substitute 175 for y in the 1st equation to find the number of nickels;
:
Check your solutions by substituting for both x and y in the 2nd equation to
confirm equality