Question 546116
Joe has a collection of nickels and dimes that is worth $2.15.
 If the number of dimes was doubled and the number of nickels was increased by 28, the value of the coins would be $4.65.
 How many nickels and dimes does he have? 
:
Let n = no. of nickels
Let d = no. of dimes
:
Write an equation for each scenario
:
"Joe has a collection of nickels and dimes that is worth $2.15."
.05n + .10d = 2.15
:
" If the number of dimes was doubled and the number of nickels was increased by 28, the value of the coins would be $4.65. "
.05(n+28) + .10(2d) = 4.64
.05n + 1.40 + .20d = 4.65
.05n + .20d = 4.65 - 1.40
.05n + .20d = 3.25
.05n + .10d = 2.15; subtract the 1st equation, from the above
------------------- eliminates n, find d
.10d = 1.10
d = {{{1.10/.10}}}
d = 11 dimes
Find the nickels
.05n + .10(11) = 2.15
.05n + 1.10 = 2.15
.05n = 2.15 - 1.10
.05n = 1.05
n = {{{1.05/.05}}}
n = 21 nickels
:
ans: 21 nickels, 11 dimes