Solving Systems Equations by Substitution
Chris has $3.85 in dimes and quarters. There are 25 coins in all. How many of each type of coin does he have?
q = # quarters value = 25q
d = #dimes value = 10d
q+ d = 25
25q + 10d = 385 from first equation d = 25-q use this in the second equation
25q + 10(25-q) = 385 now you can solve for q then d = 25-q
25q+250-10q = 385
q = 9 quarters d = 25 - q = .......