
Andrew M. answered 04/20/15
Tutor
New to Wyzant
Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors
Given the information in the problem we can set up equations and use substitution to figure out how may of each coin type Shane has.
If N = #nickels ($.05), D = #dimes ($.10), and Q = #quarters ($.25) then
The total money is added by: .05N + .1D + .25Q = 17.65
We also know that Q = N-11 since there are ll fewer quarters than nickels
and 6Q = D since there are 6 times as many dimes as quarters
So the equations we have are:
.05N + .1D + .25Q = 17.65
Q = N-11
6Q = D .... or 6(N-11) = D ..... D = 6N-66
Use substitution to find the number of nickels we have
.05N + .1(6N-66) + .25(N-11) = 17.65
.05N + .6N - 6.6 + .25N - 2.75 = 17.65
.9N -9.35 = 17.65
.9N = 17.65 + 9.35
.9N = 27
N = 27/.9
N = 30
We have 30 nickels
Q = N -11 = 30 - 11 = 19 quarters
D = 6Q = 6(19) 114 dimes
CHECK: .05N + .1D + .25Q = 17.65
.05(30) + .1(114) + .25(19) = 17.65
1.5 + 11.4 + 4.75 = 17.65
17.65 = 17.65
Since this works out correctly we see that our answer is correct