Your piggy bank contains $19.75 in dimes and quarters. There are 100 coins in all. How many dimes are there?
Mathematics
iluhvyew051415
Question
Your piggy bank contains $19.75 in dimes and quarters. There are 100 coins in all. How many dimes are there?
2 Answer

1. User Answers Heyyyagainlol
Let x = be the number of dimes and y = number of quarters.
Since the total number of coins is 100, x + y = 100.
Since the total is cent value is 19.75, comprised of .10 for dimes and .25 for quarters, we have .10x + .25y = 19.75.
This is just a system of equations. Solve one of the dozen ways that work for solving systems of linear equations.
Using substitution:
x = 100  y
Plug this into the other equation
.10 (100  y) + .25 y = 19.75
10  .10 y + .25 y = 19.75
10 + .15y = 19.75
.15 y = 9.75
y = 65
So there are 65 quarters. Since x + y = 100, there must be 35 dimes.Hope This Helps 
2. User Answers ThomasTheTank
d = no. of dimes
q = no. of quarters
$total equation
.10d + .25q = 19.75
No. of coins equation
d + q = 100
d = (100q)
Replace d
with (100q) in the $total equation
.10(100q) + .25q = 19.75
10  .10q + .25q = 19.75
10.15 q = 9.75
q =
q = 65 quarters
100  65 =
35 dimes.