SOLUTION: How can I show the equations used for the solution of this problem Number problems. Jill has $3.50 in nickels and dimes. If she has 50 coins, how many of each type of coin doe

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Question 91966: How can I show the equations used for the solution of this problem
Number problems. Jill has $3.50 in nickels and dimes. If she has 50 coins, how many of each type of coin does she have?


Answer by mathispowerful(115) About Me  (Show Source):
You can put this solution on YOUR website!
the idea is that the amount from nickels plus the amount from dimes will the the total money, that's where comes the equation.
Let N be # of nickels
Let D be # of dimes
we have
N + D = 50
5N + 10D = 350
solve this 2 by 2 system:
multiply the first equation by -5
-5N - 5D = -250
add to second equation, we get
5D = 100
D = 20
N = 50 - D
= 50 -20 = 30
so the answer is there are 30 nickels and 20 dimes.