Fabiola has 63 coins with a total value of $5.05. Some are dimes and some are nickels. How many dimes does she have?
2007-10-16 09:03:29 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
explanation will be helpful too!
thanks! :]
2007-10-16 09:04:33 · update #1
Let x be the number of dimes
so 63-x will be the number of nickels
Total value of the coin 10x + 5(63-x) = 505
Solve this eq.
10x + 315 - 5x = 505
5x = 190
x = 38
so 38 dimes and 25 nickels
check 38*10 + 25*5 = 505
2007-10-16 09:13:48 · answer #1 · answered by norman 7 · 1⤊ 0⤋
Let d = the number of dimes she has
Let n = the number of nickels she has
She has a total of 63 coins, so we can write this as an equation:
n+d=63 or solve for n:
n = 63-d
The total value is $5.05 so .10 times the number of dimes would give you the value in dimes. (.10d) and .05 times the number of nickels would give you the value in nickels. (.05n)
The sum of the values is $5.05
So:
.10d + .05n = $5.05
now plug the value of n (from the first equation) into the second equation
.10d + .05(63 - d) = 5.05
.10d + 3.15 - .05d = 5.05
.05d = 1.90
d = 38
n = 63-d = 63 - 38 = 25
so, you have 38 dimes
2007-10-16 16:13:48 · answer #2 · answered by Jen 3 · 1⤊ 0⤋