Bill has a pocket full of nickels, dimes and quarters totaling $3.45. The number of dimes is 5 times the number of nickels. The number of quarters is 7 less than 3 times the number of nickels. How many of each kind does Bill have?
Tried this way and it did not work D 5x(10) N x Q 3x-7
50x+ x + 75x-7 = 345
126x-7=345
+7 +7
126x/126=352/126
x=2.79
Can you please explain what it is I am doing wrong?
_
The number of dimes is given in terms of the number of nickels.
The number of quarters is also given in terms of the nuber of nickels.
So we let x = the number of nickels
Since
The number of dimes is 5 times the number of nickels.
Number of dimes = 5x
Since
TThe number of quarters is 7 less than 3 times the number of nickels.
Number of quarters = 3x - 7
So, since
dimes and quarters totaling $3.45
5(Number of nickels) + 10(Number of dimes) + 25(Number of quarters) = 345
5x + 10(5x) + 25(3x - 7) = 345
5x + 50x + 75x - 175 = 345
130x - 175 = 345
130x - 175 = 345
130x = 345 + 175
130x = 520
x = 
x = 4
Number of nickels = x = 4
Number of dimes = 5x = 5(5) = 20
Number of quarters = 3x - 7 = 3(4) - 7 = 12 - 7 = 5
You made two mistakes.
1. You had just x where you should have had 5x (5 cents in a nickel)
2. When you had 25(3x - 7) you multiplied the 25 by the 3x but forgot
to multiply the 25 by the -7 so you had 75x - 7 where you should have
had 75x - 175.
Edwin
