Word problem? Just need the equation.?

Question

Janet has $8.55 in nickels, dimes, and quarters. She has 7 more dimes than nickels and quarters combined. How many of each coin does she have?

Answer 1

5n+10d+25q=8.55 and n+d+q=7

now do the substitution method and figure it all out

Answer 2

Let a be the number of nickels, b the dimes and c the quarters that she has.

a5 + b10 + c25 = 855 (we convert everything into cents)

b = a + c + 7 (in absolute number of coins)

Substituting in the first equation,

5a + 10a + 10c + 70 + 25c = 855

15a + 35c = 785

We have 2 variables and only one equation. Hence we cannot get a definite solution. However since a and c are integers (a represents the number of nickels and c the number of quarters and we can't have fractions of coins), we can try for a graphical solution where both of them satisfy being integers and fulfill the condition of the total being 785.

Answer 3

ok, so the number of nickles is n, the number of dimes is d, and the number of quarters is q.
so the 1st equation is n + d + q = 8.55
the 2nd eqation states that the number of nickles plus the number of quarters plus 7 equals the number of dimes, or:
n + q + 7 = d
then you substitute to get the answers

hope that helped!