June has $1.95 in dimes and nickels. She has a total of 28 coins. How many of each type of coin does she have?
dimes --- d
nickels -- n
equation dealing with number of coins:
n+d = 28
n = 28-d
equation dealing with the value of your coins:
10d + 5n = 195
divide by 5
2d + n = 39
sub in the other equation:
2d + 28-d = 39
d = 11
n = 28-11 = 17
She has 11 dimes and 17 nickels
check:
total = 11 + 17 = 28 , check!
value: 10(11) = 5(17) = 195 , check!
My answer is correct.
Let d = # dimes and n = # nickels.
d = 2n
10d + 5n = 195
Substitute 2n for d in the second equation and solve for n. Insert that value into the first equation to solve for d. Check by putting both values into the second equation.