SOLUTION: You have a total or 21 coins, all nickels and dimes. the total value is $1.70. Write and solve a system of equations to find the number of dimes d and the number of nickles n that

Algebra ->  Inequalities -> SOLUTION: You have a total or 21 coins, all nickels and dimes. the total value is $1.70. Write and solve a system of equations to find the number of dimes d and the number of nickles n that       Log On


   

Question 72189This question is from textbook Prentice Hall Mathematics Algebra 1
: You have a total or 21 coins, all nickels and dimes. the total value is $1.70. Write and solve a system of equations to find the number of dimes d and the number of nickles n that you have. This question is from textbook Prentice Hall Mathematics Algebra 1

Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
n+d=21, n=21-d
5n+10d=170 now substitute (21-d) for n & solve.
5(21-d)+10d=170
105-5d+10d=170
5d=170-105
5d=65
d=65/5
d=13 answer for the number of dimes.
n+13=21
n=21-13
n=8 answer for the number of nickels.
proof
5*8+10*13=170
40+130=170
170=170